githelp: clean up reflog help

githelp: clean up reflog help

This referenced commands that don't exist in core. The new help
isn't great since it references an experimental extension. But
it is better than nothing.

While we're here, also add test coverage.

Differential Revision: https://phab.mercurial-scm.org/D1727

--- a/hgext/githelp.py	Mon Dec 18 20:58:00 2017 -0800
+++ b/hgext/githelp.py	Mon Dec 18 21:02:49 2017 -0800
@@ -793,9 +793,7 @@
 
     ui.status(str(cmd), "\n\n")
     ui.status(_("note: in hg commits can be deleted from repo but we always"
-              " have backups.\n"
-              "Please use 'hg backups --restore' or 'hg reset'" +
-              " to restore from backups.\n"))
+              " have backups.\n"))
 
 def reset(ui, repo, *args, **kwargs):
     cmdoptions = [

--- a/tests/test-githelp.t	Mon Dec 18 20:58:00 2017 -0800
+++ b/tests/test-githelp.t	Mon Dec 18 21:02:49 2017 -0800
@@ -271,3 +271,15 @@
   note: use hg addremove to remove files that have been deleted.
   
   hg add
+
+githelp for reflog
+
+  $ hg githelp -- git reflog
+  hg journal
+  
+  note: in hg commits can be deleted from repo but we always have backups.
+
+  $ hg githelp -- git reflog --all
+  hg journal --all
+  
+  note: in hg commits can be deleted from repo but we always have backups.