[morestatus] add helpful message to status when in bisect

Summary:
A continuation D2502125. Add more helpful output to hg status when the user is
in a bisect state.

Example output


  10/07 17:43 cdelahousse@dev4253 ~/local/clearmereg/testrepos/states/bisect
  $ hg status

  # The repository is in an unfinished *bisect* state.
  # To mark the commit good:       hg bisect --good
  # To mark the commit bad:        hg bisect --bad
  # To abort:                      hg bisect --reset

Test Plan: Tests have been updated

Reviewers: #sourcecontrol, durham

Reviewed By: durham

Subscribers: akushner

Differential Revision: https://phabricator.fb.com/D2520493

Tasks: 8563305

Signature: t1:2520493:1444288081:5da20016aaaaff77db24ecb01c404b0e11aeeb7a

morestatus.py

@@ -66,10 +66,16 @@ def mergemsg(ui):
     helpmessage(ui, 'hg commit', 'hg update --clean .    (warning: this will '
             'erase all uncommitted changed)')
 
+def bisectmsg(ui):
+    msg = _('To mark the commit good:       hg bisect --good\n'
+            'To mark the commit bad:        hg bisect --bad\n'
+            'To abort:                      hg bisect --reset\n')
+    ui.warn(prefixlines(msg))
+
 STATES = (
     # (state, file path indicating states, helpful message function)
     ('histedit', 'histedit-state', histeditmsg),
-    ('bisect', 'bisect.state', None),
+    ('bisect', 'bisect.state', bisectmsg),
     ('graft', 'graftstate', graftmsg),
     ('unshelve', 'unshelverebasestate', unshelvemsg),
     ('rebase', 'rebasestate', rebasemsg),

tests/test-morestatus.t

@@ -40,6 +40,9 @@ Test bisect state
   $ hg status
   
   # The repository is in an unfinished *bisect* state.
+  # To mark the commit good:       hg bisect --good
+  # To mark the commit bad:        hg bisect --bad
+  # To abort:                      hg bisect --reset
 
 Test hg status is normal after bisect reset
   $ hg bisect --reset