scmutil: display the optional hint when handling StorageError in catchall()

Other than CensoredNodeError (which is also a StorageError), it looks like all
exceptions with a hint display them.  I'm not sure that it makes sense to have a
hint for censored nodes, so I'm not bothering with that.

It looks like nobody is using this yet, as the tests don't change.

mercurial/scmutil.py

@@ -212,6 +212,8 b' def callcatch(ui, func):'
         ui.error(_("abort: file censored %s!\n") % inst)
     except error.StorageError as inst:
         ui.error(_("abort: %s!\n") % inst)
+        if inst.hint:
+            ui.error(_("(%s)\n") % inst.hint)
     except error.InterventionRequired as inst:
         ui.error("%s\n" % inst)
         if inst.hint: