Make tramp-completion-reread-directory-timeout obsolete (Bug#43932)

* doc/misc/tramp.texi (File name completion, Frequently Asked Questions):
Remove `tramp-completion-reread-directory-timeout'.  (Bug#43932)

* etc/NEWS: Mention tramp-completion-reread-directory-timeout as obsolete.

* lisp/net/tramp.el (tramp-completion-reread-directory-timeout):
Make it obsolete.

doc/misc/tramp.texi

@@ -2943,19 +2943,6 @@ Example:
 @end group
 @end example
 
-During file name completion, remote directory contents are re-read
-regularly to account for any changes in the filesystem that may affect
-the completion candidates.  Such re-reads can account for changes to
-the file system by applications outside Emacs (@pxref{Connection
-caching}).
-
-@defopt tramp-completion-reread-directory-timeout
-The timeout is number of seconds since last remote command for
-rereading remote directory contents.  A value of 0 re-reads
-immediately during file name completion, @code{nil} uses cached
-directory contents.
-@end defopt
-
 
 @node Ad-hoc multi-hops
 @section Declaring multiple hops in the file name
@@ -3909,9 +3896,6 @@ files are not independently updated outside @value{tramp}'s control.
 That cache cleanup will be necessary if the remote directories or
 files are updated independent of @value{tramp}.
 
-Set @code{tramp-completion-reread-directory-timeout} to @code{nil} to
-speed up completions, @ref{File name completion}.
-
 Disable version control to avoid delays:
 
 @lisp

etc/NEWS

@@ -38,6 +38,10 @@ This is a bug-fix release with no new features.
 
 * Changes in Specialized Modes and Packages in Emacs 27.2
 
+** Tramp
+
+*** The user option 'tramp-completion-reread-directory-timeout' is made obsolete.
+
 
 * New Modes and Packages in Emacs 27.2
 
@@ -231,7 +235,7 @@ it won't work right without some adjustment:
 Units that are ordered after 'emacs.service' will only be started
 after Emacs has finished initialization and is ready for use, and
 Emacs needs to be built with systemd support.  (If your Emacs is
-installed in a non-standard location and you copied the emacs.service
+installed in a non-standard location and you copied the "emacs.service"
 file to e.g. "~/.config/systemd/user/", you will need to copy the new
 version of the file again.)
 

lisp/net/tramp.el

@@ -1224,6 +1224,8 @@ have been gone since last remote command execution.  A value of t
 would require an immediate reread during filename completion, nil
 means to use always cached values for the directory contents."
   :type '(choice (const nil) (const t) integer))
+(make-obsolete-variable
+ 'tramp-completion-reread-directory-timeout 'remote-file-name-inhibit-cache "27.2")
 
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