Documentation: Refer to git-rebase(1) to warn against rewriting

This points readers at the "Recovering from upstream rebase" warning
in git-rebase(1) when we talk about rewriting published history in the
'reset', 'commit --amend', and 'filter-branch' documentation.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-commit.txt

@@ -144,6 +144,10 @@ It is a rough equivalent for:
 ------
 but can be used to amend a merge commit.
 --
++
+You should understand the implications of rewriting history if you
+amend a commit that has already been published.  (See the "RECOVERING
+FROM UPSTREAM REBASE" section in linkgit:git-rebase[1].)
 
 -i::
 --include::

Documentation/git-filter-branch.txt

@@ -36,7 +36,9 @@ the objects and will not converge with the original branch.  You will not
 be able to easily push and distribute the rewritten branch on top of the
 original branch.  Please do not use this command if you do not know the
 full implications, and avoid using it anyway, if a simple single commit
-would suffice to fix your problem.
+would suffice to fix your problem.  (See the "RECOVERING FROM UPSTREAM
+REBASE" section in linkgit:git-rebase[1] for further information about
+rewriting published history.)
 
 Always verify that the rewritten version is correct: The original refs,
 if different from the rewritten ones, will be stored in the namespace

Documentation/git-reset.txt

@@ -82,7 +82,9 @@ $ git reset --hard HEAD~3   <1>
 +
 <1> The last three commits (HEAD, HEAD^, and HEAD~2) were bad
 and you do not want to ever see them again.  Do *not* do this if
-you have already given these commits to somebody else.
+you have already given these commits to somebody else.  (See the
+"RECOVERING FROM UPSTREAM REBASE" section in linkgit:git-rebase[1] for
+the implications of doing so.)
 
 Undo a commit, making it a topic branch::
 +