Documentation: make AsciiDoc links always point to HTML files

AsciiDoc's "link" is supposed to create hyperlinks for HTML output, so
prefer a "link" to point to an HTML file instead of a text file if an HTML
version of the file is being generated. For RelNotes, keep pointing to
text files as no equivalent HTML files are generated.

If appropriate, also update the link description to not contain the linked
file's extension.

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/everyday.txt

@@ -304,7 +304,7 @@ and maintain access to the repository by developers.
   * linkgit:git-shell[1] can be used as a 'restricted login shell'
     for shared central repository users.
 
-link:howto/update-hook-example.txt[update hook howto] has a good
+link:howto/update-hook-example.html[update hook howto] has a good
 example of managing a shared central repository.
 
 

Documentation/git-credential.txt

@@ -20,7 +20,7 @@ usernames and passwords. The git-credential command exposes this
 interface to scripts which may want to retrieve, store, or prompt for
 credentials in the same manner as Git. The design of this scriptable
 interface models the internal C API; see
-link:technical/api-credentials.txt[the Git credential API] for more
+link:technical/api-credentials.html[the Git credential API] for more
 background on the concepts.
 
 git-credential takes an "action" option on the command-line (one of

Documentation/git-rebase.txt

@@ -322,7 +322,7 @@ You may find this (or --no-ff with an interactive rebase) helpful after
 reverting a topic branch merge, as this option recreates the topic branch with
 fresh commits so it can be remerged successfully without needing to "revert
 the reversion" (see the
-link:howto/revert-a-faulty-merge.txt[revert-a-faulty-merge How-To] for details).
+link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for details).
 
 --ignore-whitespace::
 --whitespace=<option>::
@@ -416,7 +416,7 @@ Without --interactive, this is a synonym for --force-rebase.
 You may find this helpful after reverting a topic branch merge, as this option
 recreates the topic branch with fresh commits so it can be remerged
 successfully without needing to "revert the reversion" (see the
-link:howto/revert-a-faulty-merge.txt[revert-a-faulty-merge How-To] for details).
+link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for details).
 
 include::merge-strategies.txt[]
 

Documentation/git-revert.txt

@@ -59,7 +59,7 @@ brought in by the merge.  As a result, later merges will only bring in tree
 changes introduced by commits that are not ancestors of the previously
 reverted merge.  This may or may not be what you want.
 +
-See the link:howto/revert-a-faulty-merge.txt[revert-a-faulty-merge How-To] for
+See the link:howto/revert-a-faulty-merge.html[revert-a-faulty-merge How-To] for
 more details.
 
 --no-edit::

Documentation/gitcvs-migration.txt

@@ -157,7 +157,7 @@ points.  You can use these, for example, to send all commits to the shared
 repository to a mailing list.  See linkgit:githooks[5].
 
 You can enforce finer grained permissions using update hooks.  See
-link:howto/update-hook-example.txt[Controlling access to branches using
+link:howto/update-hook-example.html[Controlling access to branches using
 update hooks].
 
 Providing CVS Access to a Git Repository

Documentation/user-manual.txt

@@ -1977,7 +1977,7 @@ $ git clone http://yourserver.com/~you/proj.git
 -------------------------------------------------
 
 (See also
-link:howto/setup-git-server-over-http.txt[setup-git-server-over-http]
+link:howto/setup-git-server-over-http.html[setup-git-server-over-http]
 for a slightly more sophisticated setup using WebDAV which also
 allows pushing over HTTP.)
 
@@ -3191,7 +3191,7 @@ those "loose" objects.
 You can save space and make Git faster by moving these loose objects in
 to a "pack file", which stores a group of objects in an efficient
 compressed format; the details of how pack files are formatted can be
-found in link:technical/pack-format.txt[technical/pack-format.txt].
+found in link:technical/pack-format.html[pack format].
 
 To put the loose objects into a pack, just run git repack: