resolve: mention merge-tools topic in help

mercurial/commands.py

@@ -4603,7 +4603,8 b' def resolve(ui, repo, *pats, **opts):'
     setting, or a command-line merge tool like ``diff3``. The resolve
     command is used to manage the files involved in a merge, after
     :hg:`merge` has been run, and before :hg:`commit` is run (i.e. the
-    working directory must have two parents).
+    working directory must have two parents). See :hg:`help
+    merge-tools` for information on configuring merge tools.
 
     The resolve command can be used in the following ways: