Use sphinx.ext.extlinks to generate frequently used links

Documentation see here:
http://sphinx-doc.org/ext/extlinks.html

users/faq.rst

@@ -210,9 +210,7 @@ settings at default and use an ssh port forward to access it. For example,
 will log you into othercomputer.example.com, and present the *remote* Syncthing
 GUI on http://localhost:9090 on your *local* computer. You should not open more
 than one Syncthing GUI in a single browser due to conflicting X-CSRFTokens. Any
-modification will be rejected. See `Issue 720
-<https://github.com/syncthing/syncthing/issues/720#issuecomment-58159631>`__ to
-work around this limitation.
+modification will be rejected. See :issue:`720` to work around this limitation.
 
 The CSRF tokens are stored using cookies. Therefore, if you get the message
 ``Syncthing seems to be experiencing a problem processing your request``, you

users/ignoring.rst

@@ -124,16 +124,14 @@ Assume two nodes, Alice and Bob, where Alice has 100 files to share, but
 Bob ignores 25 of these. From Alice's point of view Bob will become
 about 75% in sync (the actual number depends on the sizes of the
 individual files) and remain in "Syncing" state even though it is in
-fact not syncing anything (issue
-`#623 <https://github.com/syncthing/syncthing/issues/623>`__). From
+fact not syncing anything (:issue:`623`). From
 Bob's point of view it's 100% up to date but will show fewer files in
 both the local and global view.
 
 If Bob adds files that have already been synced to the ignore list, they
 will remain in the "global" view but disappear from the "local" view.
 The end result is more files in the global repository than in the local,
-but still 100% in sync (issue
-`#624 <https://github.com/syncthing/syncthing/issues/624>`__). From
+but still 100% in sync (:issue:`624`). From
 Alice's point of view, Bob will remain 100% in sync until the next
 reconnect, because Bob has already announce that he has the files that
 are now suddenly ignored.