visibility: improve the message when accessing filtered obsolete rev When trying to access filtered revision, it is likely because they have been obsoleted by an obs-marker. The current message shows how to access the revision anyway: abort: hidden revision '13bedc178fce'! But in the case of an obsoleted revision, the user is likely to want to update to or use the successor of the revision. We update the message to display more information about the obsolescence fate of the revision in the following cases: abort: hidden revision '13bedc178fce' is pruned! abort: hidden revision '13bedc178fce' has diverged! abort: hidden revision '13bedc178fce' was rewritten as X, Y and 2 more! Differential Revision: https://phab.mercurial-scm.org/D1591

--- a/tests/test-log.t	Fri Dec 29 03:37:36 2017 +0530
+++ b/tests/test-log.t	Fri Jan 05 09:12:08 2018 +0100
@@ -1827,7 +1827,7 @@
   1:a765632148dc55d38c35c4f247c618701886cb2f
   0:9f758d63dcde62d547ebfb08e1e7ee96535f2b05
   $ hg log -r a
-  abort: hidden revision 'a'!
+  abort: hidden revision 'a' is pruned!
   (use --hidden to access hidden revisions)
   [255]
 
@@ -1885,7 +1885,7 @@
   2:94375ec45bddd2a824535fc04855bd058c926ec0
   3:d7d28b288a6b83d5d2cf49f10c5974deed3a1d2e
   $ hg log -T'{rev}:{node}\n' -r:0
-  abort: hidden revision '0'!
+  abort: hidden revision '0' is pruned!
   (use --hidden to access hidden revisions)
   [255]
   $ hg log -T'{rev}:{node}\n' -f