Correct variable markup in manuals

* doc/lispref/minibuf.texi (Completion in Buffers): Fix markup.
* doc/lispref/text.texi (Filling): Likewise.
* doc/misc/dired-x.texi (Advanced Mark Commands): Likewise.
* doc/misc/epa.texi (Encrypting/decrypting gpg files): Likewise.
(Encrypting/decrypting gpg files): Likewise.
* doc/misc/tramp.texi (External methods): Likewise.
(Default Method): Likewise.
* doc/misc/viper.texi (Editing in Insert State): Likewise.
(File and Buffer Handling): Likewise.
* doc/misc/gnus.texi (Mail Source Customization): Likewise.
* doc/misc/url.texi (Customization): Likewise.  Note obsolete
status of url-temporary-directory.

doc/lispref/minibuf.texi

@@ -1916,7 +1916,7 @@ may internally call functions in @code{completion-at-point-functions}
 many times, but care about the value of @var{collection} for only some
 of these calls.  By supplying a function for @var{collection}, Emacs
 can defer generating completions until necessary.  You can use
-@var{completion-table-dynamic} to create a wrapper function:
+@code{completion-table-dynamic} to create a wrapper function:
 
 @smallexample
 ;; Avoid this pattern.

doc/lispref/text.texi

@@ -1637,7 +1637,7 @@ This function returns the proper justification style to use for filling
 the text around point.
 
 This returns the value of the @code{justification} text property at
-point, or the variable @var{default-justification} if there is no such
+point, or the variable @code{default-justification} if there is no such
 text property.  However, it returns @code{nil} rather than @code{none}
 to mean ``don't justify''.
 @end defun

doc/misc/dired-x.texi

@@ -733,7 +733,7 @@ and an optional argument @var{marker-char} specifies the marker used.
 @findex dired-mark-suffix
 Mark all files with a certain suffix for use in later commands.  A @samp{.}
 is not automatically prepended to the string entered, you must type it
-explicitly.  This is different from @var{dired-mark-extension} which prepends
+explicitly.  This is different from @code{dired-mark-extension} which prepends
 a @samp{.} if not present.
 If invoked with prefix argument @kbd{C-u}, this command unmarks files instead.
 If called with the @kbd{C-u C-u} prefix, asks for a character to use

doc/misc/epa.texi

@@ -363,7 +363,7 @@ Similarly, when you save the buffer to a @file{foo.gpg} file,
 encrypted data is written.
 
 The file name pattern for encrypted files can be controlled by
-@var{epa-file-name-regexp}.
+@code{epa-file-name-regexp}.
 
 @defvar epa-file-name-regexp
 Regexp which matches filenames treated as encrypted.
@@ -392,7 +392,7 @@ public key encryption.
 @end deffn
 
 You can also change the default behavior with the variable
-@var{epa-file-select-keys}.
+@code{epa-file-select-keys}.
 
 @defvar epa-file-select-keys
 Control whether or not to pop up the key selection dialog.

doc/misc/gnus.texi

@@ -15174,7 +15174,7 @@ All new mail files will get this file mode.  The default is @code{#o600}.
 @item mail-source-movemail-program
 @vindex mail-source-movemail-program
 If non-@code{nil}, name of program for fetching new mail.  If
-@code{nil}, @code{movemail} in @var{exec-directory}.
+@code{nil}, @code{movemail} in @code{exec-directory}.
 
 @end table
 

doc/misc/tramp.texi

@@ -809,7 +809,7 @@ External methods save on the overhead of encoding and decoding of
 inline methods.
 
 Since external methods have the overhead of opening a new channel,
-files smaller than @var{tramp-copy-size-limit} still use inline
+files smaller than @code{tramp-copy-size-limit} still use inline
 methods.
 
 @table @asis
@@ -1201,7 +1201,7 @@ Start by using an inline method.
 External methods might be more efficient for large files, but most
 @value{tramp} users edit small files more often than large files.
 
-Enable compression, @var{tramp-inline-compress-start-size}, for a
+Enable compression, @code{tramp-inline-compress-start-size}, for a
 performance boost for large files.
 
 Since @command{ssh} has become the most common method of remote host

doc/misc/url.texi

@@ -1271,8 +1271,9 @@ operation at startup.
 @item TMPDIR
 @vindex TMPDIR
 @vindex url-temporary-directory
-If this is defined, @var{url-temporary-directory} is initialized from
+If this is defined, @code{url-temporary-directory} is initialized from
-it.
+it.  This variable was obsoleted in 23.1, please use
+@code{temporary-file-directory} instead.
 @end table
 
   The following user options affect the general operation of

doc/misc/viper.texi

@@ -3579,7 +3579,7 @@ Viper customization file.  @xref{Viper Specials}, for details.
 Minibuffer can be edited similarly to Insert state, and you can switch
 between Insert/Replace/Vi states at will.
 Some users prefer plain Emacs feel in the minibuffer.  To this end, set
-@var{viper-vi-style-in-minibuffer} to @code{nil}.
+@code{viper-vi-style-in-minibuffer} to @code{nil}.
 
 @cindex Insert state
 
@@ -4063,15 +4063,15 @@ Edit <count> file, or edit files.  The count comes from @kbd{:args}.
 Like @kbd{:n}, but the meaning of the variable
 @var{ex-cycle-other-window} is reversed.
 @item :b
-Switch to another buffer.  If @var{ex-cycle-other-window} is @code{t},
+Switch to another buffer.  If @code{ex-cycle-other-window} is @code{t},
 switch in another window.  Buffer completion is supported.
-The variable @var{viper-read-buffer-function} controls which function is
+The variable @code{viper-read-buffer-function} controls which function is
 actually used to read the buffer name. The default is @code{read-buffer},
 but better alternatives are also available in Emacs (e.g.,
 @code{ido-read-buffer}).
 @vindex @var{viper-read-buffer-function}
 @item :B
-Like @kbd{:b}, but the meaning of @var{ex-cycle-other-window} is reversed.
+Like @kbd{:b}, but the meaning of code{ex-cycle-other-window} is reversed.
 @item :<address>r <name>
 Read the file <name> into the buffer after the line <address>.
 @item v, V, C-v