help: use hg role of mini reST to make hyper link in HTML page

mercurial/help/config.txt

@@ -436,12 +436,12 b' effect and style see :hg:`help color`.'
 ------------
 
 ``status.relative``
-    Make paths in ``hg status`` output relative to the current directory.
+    Make paths in :hg:`status` output relative to the current directory.
     (default: False)
 
 ``update.requiredest``
-    Require that the user pass a destination when running ``hg update``.
-    For example, ``hg update .::`` will be allowed, but a plain ``hg update``
+    Require that the user pass a destination when running :hg:`update`.
+    For example, :hg:`update .::` will be allowed, but a plain :hg:`update`
     will be disallowed.
     (default: False)