status: add support for log-like template keywords and functions

It's bound to ctx2 since "hg status" can be considered to show the status
of the files at ctx2 given ctx1 as the base.

mercurial/commands.py

@@ -5117,6 +5117,7 b' def status(ui, repo, *pats, **opts):'
             label = 'status.' + state
             for f in files:
                 fm.startitem()
+                fm.context(ctx=ctx2)
                 fm.condwrite(showchar, 'status', '%s ', char, label=label)
                 fm.write('path', fmt, repo.pathto(f, cwd), label=label)
                 if f in copy:

tests/test-status.t

@@ -213,6 +213,16 b' hg status -A:'
   C .hgignore
   C modified
 
+  $ hg status -A -T '{status} {path} {node|shortest}\n'
+  A added ffff
+  A copied ffff
+  R removed ffff
+  ! deleted ffff
+  ? unknown ffff
+  I ignored ffff
+  C .hgignore ffff
+  C modified ffff
+
   $ hg status -A -Tjson
   [
    {