git-gc --prune is deprecated

25ee9731c1 made the '--prune' option
deprecated and removed its description from the git-gc man page. This
patch removes all references to this option from the rest of the Git
documentation.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/everyday.txt

@@ -48,14 +48,12 @@ $ git gc <3>
 repository health reasonably well.
 <2> check how many loose objects there are and how much
 disk space is wasted by not repacking.
-<3> repacks the local repository and performs other housekeeping tasks. Running
+<3> repacks the local repository and performs other housekeeping tasks.
-without `--prune` is a safe operation even while other ones are in progress.
 
 Repack a small project into single pack.::
 +
 ------------
 $ git gc <1>
-$ git gc --prune
 ------------
 +
 <1> pack all the objects reachable from the refs into one pack,
@@ -182,7 +180,7 @@ $ git pull <3>
 $ git log -p ORIG_HEAD.. arch/i386 include/asm-i386 <4>
 $ git pull git://git.kernel.org/pub/.../jgarzik/libata-dev.git ALL <5>
 $ git reset --hard ORIG_HEAD <6>
-$ git gc --prune <7>
+$ git gc <7>
 $ git fetch --tags <8>
 ------------
 +

Documentation/user-manual.txt

@@ -1548,22 +1548,7 @@ dangling tree b24c2473f1fd3d91352a624795be026d64c8841f
 
 Dangling objects are not a problem.  At worst they may take up a little
 extra disk space.  They can sometimes provide a last-resort method for
-recovering lost work--see <<dangling-objects>> for details.  However, if
+recovering lost work--see <<dangling-objects>> for details.
-you wish, you can remove them with linkgit:git-prune[1] or the `--prune`
-option to linkgit:git-gc[1]:
-
--------------------------------------------------
-$ git gc --prune
--------------------------------------------------
-
-This may be time-consuming.  Unlike most other git operations (including
-git-gc when run without any options), it is not safe to prune while
-other git operations are in progress in the same repository.
-
-If linkgit:git-fsck[1] complains about sha1 mismatches or missing
-objects, you may have a much more serious problem; your best option is
-probably restoring from backups.  See
-<<recovering-from-repository-corruption>> for a detailed discussion.
 
 [[recovering-lost-changes]]
 Recovering lost changes