Minor Texinfo usage fix.

lispref/lists.texi

@@ -384,11 +384,11 @@ If @var{n} is zero or negative, @code{nthcdr} returns all of
 @end defun
 
 @defun last list &optional n
-This function returns the last link of @var{list}.  The
-@code{car} of this link is the list's last element.  If @var{list} is
-null, @code{nil} is returned.  If @var{n} is non-nil the
-@var{n}-th-to-last link is returned instead, or the whole @var{list} if
-@var{n} is bigger than @var{list}'s length.
+This function returns the last link of @var{list}.  The @code{car} of
+this link is the list's last element.  If @var{list} is null,
+@code{nil} is returned.  If @var{n} is non-@code{nil}, the
+@var{n}th-to-last link is returned instead, or the whole of @var{list}
+if @var{n} is bigger than @var{list}'s length.
 @end defun
 
 @defun safe-length list

lispref/minibuf.texi

@@ -184,12 +184,12 @@ arguments @var{prompt} and @var{initial} are used as in
 @code{read-from-minibuffer}.  The keymap used is
 @code{minibuffer-local-map}.
 
-The optional argument @var{history}, if non-nil, specifies a history
-list and optionally the initial position in the list.  The optional
-argument @var{default} specifies a default value to return if the user
-enters null input; it should be a string.  The optional argument
-@var{inherit-input-method} specifies whether to inherit the current
-buffer's input method.
+The optional argument @var{history}, if non-@code{nil}, specifies a
+history list and optionally the initial position in the list.  The
+optional argument @var{default} specifies a default value to return if
+the user enters null input; it should be a string.  The optional
+argument @var{inherit-input-method} specifies whether to inherit the
+current buffer's input method.
 
 This function is a simplified interface to the
 @code{read-from-minibuffer} function:

lispref/modes.texi

@@ -2105,9 +2105,9 @@ which construct their text programmatically, such as
 If your mode does not use any of the other machinery of Font Lock
 (i.e. it only uses the @code{font-lock-face} property), you can tell
 Emacs not to load all of font-lock.el (unless it's already loaded), by
-setting the variable @code{font-lock-core-only} to non-nil as part of
-the @code{font-lock-defaults} settings.  Here is the canonical way to
-do this:
+setting the variable @code{font-lock-core-only} to non-@code{nil} as
+part of the @code{font-lock-defaults} settings.  Here is the canonical
+way to do this:
 
 @example
 (set (make-local-variable 'font-lock-defaults)

lispref/nonascii.texi

@@ -273,8 +273,8 @@ text representations.
      @result{} t
 @end example
 
-If the optional argument @var{genericp} is non-nil, this function
-returns @code{t} if @var{charcode} is a generic character
+If the optional argument @var{genericp} is non-@code{nil}, this
+function returns @code{t} if @var{charcode} is a generic character
 (@pxref{Splitting Characters}).
 @end defun
 

lispref/variables.texi

@@ -576,11 +576,12 @@ this feature is largely obsoleted by @code{defcustom}
 (@pxref{Customization}).
 
   @strong{Warning:} If the @code{defconst} and @code{defvar} special
-forms are used while the variable has a local binding, they set the
-local binding's value; the global binding is not changed.  This is not
-what you usually want.  To prevent it, use these special forms at top
-level in a file, where normally no local binding is in effect, and make
-sure to load the file before making a local binding for the variable.
+forms are used while the variable has a local binding (made with
+@code{let}, or a function argument), they set the local-binding's
+value; the top-level binding is not changed.  This is not what you
+usually want.  To prevent it, use these special forms at top level in
+a file, where normally no local binding is in effect, and make sure to
+load the file before making a local binding for the variable.
 
 @node Tips for Defining
 @section Tips for Defining Variables Robustly
@@ -1749,7 +1750,8 @@ for one of these variables is ignored.
 @end defvar
 
 @defun risky-local-variable-p sym
-Returns non-nil if @var{sym} is risky for any of the reasons stated above.
+Returns non-@code{nil} if @var{sym} is risky for any of the reasons
+stated above.
 @end defun
 
   The @samp{Eval:} ``variable'' is also a potential loophole, so Emacs