Add user options mentioned in the Eshell manual to the variable index

* doc/misc/eshell.texi: Make variable index entries use "code" style,
and add indexing for any options already in the manual.

doc/misc/eshell.texi

@@ -4,7 +4,7 @@
 @settitle Eshell: The Emacs Shell
 @include docstyle.texi
 @defindex cm
-@synindex vr fn
+@syncodeindex vr fn
 @c %**end of header
 
 @copying
@@ -442,6 +442,7 @@ overwriting files.  If both settings are non-@code{nil}, the commands
 always prompt.  If both settings are @code{nil} (the default), the
 commands signal an error.
 
+@vindex eshell-default-target-is-dot
 Several commands observe the value of
 @code{eshell-default-target-is-dot}.  If non-@code{nil}, then the
 default target for the commands @command{cp}, @command{mv}, and
@@ -505,6 +506,8 @@ directory.
 With @kbd{cd -42}, you can access the directory stack slots by number.
 
 @item
+@vindex eshell-cd-shows-directory
+@vindex eshell-list-files-after-cd
 If @code{eshell-cd-shows-directory} is non-@code{nil}, @command{cd}
 will report the directory it changes to.  If
 @code{eshell-list-files-after-cd} is non-@code{nil}, then @command{ls}
@@ -528,6 +531,8 @@ buffer.
 Copy a file to a new location or copy multiple files to the same
 directory.
 
+@vindex eshell-cp-overwrite-files
+@vindex eshell-cp-interactive-query
 If @code{eshell-cp-overwrite-files} is non-@code{nil}, then
 @command{cp} will overwrite files without warning.  If
 @code{eshell-cp-interactive-query} is non-@code{nil}, then
@@ -545,6 +550,7 @@ Compare files using Emacs's internal @code{diff} (not to be confused
 with @code{ediff}).  @xref{Comparing Files, , , emacs, The GNU Emacs
 Manual}.
 
+@vindex eshell-plain-diff-behavior
 If @code{eshell-plain-diff-behavior} is non-@code{nil}, then this
 command does not use Emacs's internal @code{diff}.  This is the same
 as using @samp{alias diff '*diff $*'}.
@@ -572,6 +578,7 @@ Echoes its input.  By default, this prints in a Lisp-friendly fashion
 prints a list of all the arguments; otherwise, it prints the empty
 string.
 
+@vindex eshell-plain-echo-behavior
 If @code{eshell-plain-echo-behavior} is non-@code{nil}, @command{echo}
 will try to behave more like a plain shell's @command{echo}, printing
 each argument as a string, separated by a space.
@@ -592,6 +599,7 @@ cmd*}.
 
 @item exit
 @cmindex exit
+@vindex eshell-kill-on-exit
 Exit Eshell and save the history.  By default, this command kills the
 Eshell buffer, but if @code{eshell-kill-on-exit} is @code{nil}, then
 the buffer is merely buried instead.
@@ -615,6 +623,7 @@ The @command{grep} commands are compatible with GNU @command{grep},
 but use Emacs's internal @code{grep} instead.
 @xref{Grep Searching, , , emacs, The GNU Emacs Manual}.
 
+@vindex eshell-plain-grep-behavior
 If @code{eshell-plain-grep-behavior} is non-@code{nil}, then these
 commands do not use Emacs's internal @code{grep}.  This is the same as
 using @samp{alias grep '*grep $*'}, though this setting applies to all
@@ -653,6 +662,8 @@ and @code{("foo" "bar")} both evaluate to @code{("foo" "bar")}.
 @cmindex ln
 Create links to files.
 
+@vindex eshell-ln-overwrite-files
+@vindex eshell-ln-interactive-query
 If @code{eshell-ln-overwrite-files} is non-@code{nil}, @command{ln}
 will overwrite files without warning.  If
 @code{eshell-ln-interactive-query} is non-@code{nil}, then
@@ -664,6 +675,7 @@ Alias to Emacs's @code{locate} function, which simply runs the external
 @command{locate} command and parses the results.
 @xref{Dired and Find, , , emacs, The GNU Emacs Manual}.
 
+@vindex eshell-plain-locate-behavior
 If @code{eshell-plain-locate-behavior} is non-@code{nil}, then Emacs's
 internal @code{locate} is not used.  This is the same as using
 @samp{alias locate '*locate $*'}.
@@ -672,21 +684,25 @@ internal @code{locate} is not used.  This is the same as using
 @cmindex ls
 Lists the contents of directories.
 
+@vindex eshell-ls-use-colors
 If @code{eshell-ls-use-colors} is non-@code{nil}, the contents of a
 directory is color-coded according to file type and status.  These
 colors and the regexps used to identify their corresponding files can
 be customized via @w{@kbd{M-x customize-group @key{RET} eshell-ls @key{RET}}}.
 
+@vindex eshell-ls-date-format
 The user option @code{eshell-ls-date-format} determines how the date
 is displayed when using the @option{-l} option.  The date is produced
 using the function @code{format-time-string} (@pxref{Time Parsing,,,
 elisp, GNU Emacs Lisp Reference Manual}).
 
+@vindex eshell-ls-initial-args
 The user option @code{eshell-ls-initial-args} contains a list of
 arguments to include with any call to @command{ls}.  For example, you
 can include the option @option{-h} to always use a more human-readable
 format.
 
+@vindex eshell-ls-default-blocksize
 The user option @code{eshell-ls-default-blocksize} determines the
 default blocksize used when displaying file sizes with the option
 @option{-s}.
@@ -710,6 +726,8 @@ Make new directories.
 @cmindex mv
 Move or rename files.
 
+@vindex eshell-mv-overwrite-files
+@vindex eshell-mv-interactive-query
 If @code{eshell-mv-overwrite-files} is non-@code{nil}, @command{mv}
 will overwrite files without warning.  If
 @code{eshell-mv-interactive-query} is non-@code{nil}, @command{mv}
@@ -734,6 +752,8 @@ Print the arguments separated by newlines.
 Push the current directory onto the directory stack, then change to
 another directory.
 
+@vindex eshell-pushd-dunique
+@vindex eshell-pushd-dextract
 If @code{eshell-pushd-dunique} is non-@code{nil}, then only unique
 directories will be added to the stack.  If
 @code{eshell-pushd-dextract} is non-@code{nil}, then @samp{pushd
@@ -748,6 +768,8 @@ Prints the current working directory.
 Removes files, buffers, processes, or Emacs Lisp symbols, depending on
 the argument.
 
+@vindex eshell-rm-interactive-query
+@vindex eshell-rm-removes-directories
 If @code{eshell-rm-interactive-query} is non-@code{nil}, @command{rm}
 will prompt before removing anything.  If
 @code{eshell-rm-removes-directories} is non-@code{nil}, then
@@ -1036,6 +1058,7 @@ Tramp, may add extra information to this value.
 @section Aliases
 
 @vindex $*
+@vindex eshell-aliases-file
 Aliases are commands that expand to a longer input line.  For example,
 @command{ll} is a common alias for @code{ls -l}, and would be defined
 with the command invocation @kbd{alias ll 'ls -l $*'}; with this defined,
@@ -1081,6 +1104,7 @@ slash module (@pxref{Electric forward slash}).
 @node History
 @section History
 @cmindex history
+@vindex eshell-history-size
 The @samp{history} command shows all commands kept in the history ring
 as numbered list.  If the history ring contains
 @code{eshell-history-size} commands, those numbers change after every
@@ -1100,6 +1124,7 @@ command beginning with @code{foo}, and @samp{!?foo} to the last
 command containing @code{foo}.  The n-th argument of the last command
 beginning with @code{foo} is accessible by @code{!foo:n}.
 
+@vindex eshell-history-file-name
 The history ring is loaded from a file at the start of every session,
 and written back to the file at the end of every session.  The file path
 is specified in @code{eshell-history-file-name}.  Unlike other shells,
@@ -1285,6 +1310,7 @@ to @code{$(@var{lisp})}, this is identical to @code{@{@var{command}@}}
 when on its own, but the @code{$} allows it to be used inside double
 quotes or as part of a string.
 
+@vindex eshell-convert-numeric-arguments
 Normally, the output is split line-by-line, returning a list (or the
 first element if there's only one line of output); if
 @code{eshell-convert-numeric-arguments} is non-@code{nil} and every
@@ -1350,12 +1376,12 @@ the result of @var{expr} is not a string or a sequence.
 
 @node Globbing
 @section Globbing
-@vindex eshell-glob-case-insensitive
 Eshell's globbing syntax is very similar to that of Zsh
 (@pxref{Filename Generation, , , zsh, The Z Shell Manual}).  Users
 coming from Bash can still use Bash-style globbing, as there are no
 incompatibilities.
 
+@vindex eshell-glob-case-insensitive
 By default, globs are case sensitive, except on MS-DOS/MS-Windows
 systems.  You can control this behavior via the
 @code{eshell-glob-case-insensitive} option.  You can further customize
@@ -1709,6 +1735,9 @@ garbage output, since the Eshell buffer is not a terminal emulator.
 Eshell solves this problem by running such programs in Emacs's
 terminal emulator.
 
+@vindex eshell-visual-commands
+@vindex eshell-visual-subcommands
+@vindex eshell-visual-options
 Programs that need a terminal to display output properly are referred
 to in this manual as ``visual commands'', because they are not simply
 line-oriented.  You must tell Eshell which commands are visual, by
@@ -1926,6 +1955,7 @@ modules.@footnote{ERC provides a similar module facility.}
 @node Optional modules
 @section Optional modules
 
+@vindex eshell-modules-list
 In addition to the various modules enabled by default (documented
 above), Eshell provides several other modules which are @emph{not}
 enabled by default.  If you want to enable these, you can add them to
@@ -1953,6 +1983,7 @@ text, @kbd{C-u} to kill the current input text, and @kbd{C-w} to
 @code{backward-kill-word}.  If the history module is enabled, it also
 binds @kbd{C-p} and @kbd{C-n} to move through the input history.
 
+@vindex eshell-confine-point-to-input
 If @code{eshell-confine-point-to-input} is non-@code{nil}, this module
 prevents certain commands from causing the point to leave the input
 area, such as @code{backward-word}, @code{previous-line}, etc.