zsh_completion: complete files from `hg st -mar` for commit and diff

Useful to have and is consistent with our bash completion file.

This is also an improvement coming from upstream, downstream or sidestream
(depends on how you look at it) hg completion file -- the one that lives in
zsh's own repo.

Differential Revision: https://phab.mercurial-scm.org/D4263

contrib/zsh_completion

@@ -245,10 +245,10 b' typeset -A _hg_cmd_globals'
   _wanted files expl 'missing files' _multi_parts / status_files
 }
 
-_hg_modified() {
+_hg_committable() {
   typeset -a status_files
-  _hg_status m
-  _wanted files expl 'modified files' _multi_parts / status_files
+  _hg_status mar
+  _wanted files expl 'modified, added or removed files' _multi_parts / status_files
 }
 
 _hg_resolve() {
@@ -570,7 +570,7 b' typeset -A _hg_cmd_globals'
   '(--user -u)'{-u+,--user=}'[record user as commiter]:user:' \
   '--amend[amend the parent of the working dir]' \
   '--close-branch[mark a branch as closed]' \
-  '*:file:_hg_files'
+  '*:file:_hg_committable'
 }
 
 _hg_cmd_copy() {
@@ -599,7 +599,7 b' typeset -A _hg_cmd_globals'
     then
       _hg_files
     else
-      _hg_modified
+      _hg_committable
     fi
   fi
 }