typing: add minimal annotations to cmd_impls/graft.py to pytype with 3.10

I'm not sure why the same version of pytype passed in CI with Python 3.11.
What's failing on 3.10 is related to `statedata`, which is keyed on bytes, but
has various value types.  It looks like these several types are treated as a
union when run with 3.10, and then all of them need to have the same attributes.
This will take awhile to untangle, because `TypedDict` requires str keys, so
we'll either have to change the keys (and whoever calls this), or migrate to a
class with typed fields (and change all of the callers).  There are some changes
to this module currently in-flight, so I'm opting for the minimal changes here
to minimally affect that, while keeping my ability to run pytype locally and
track the changes.

It's worth pointing out that I'm starting to use py3.9 type hints here, i.e.
`Foo | None` instead of `Optional[Foo]`.  That's fine even with py3.8 support
because of the `from __future__ import annotations`, which delays evaluation.
We already don't support pytype checking with all of the runtime supported
versions of Python since at least 0851d94bfdaa, with the `ByteString` usage.

The errors at the start of this series were:

    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 238, in _graft_revisions: No attribute 'get' on bool [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 238, in _graft_revisions: No attribute 'get' on bytes [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 239, in _graft_revisions: No attribute 'get' on bool [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 239, in _graft_revisions: No attribute 'get' on bytes [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 241, in _graft_revisions: No attribute 'get' on bool [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 241, in _graft_revisions: No attribute 'get' on bytes [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 260, in _graft_revisions: unsupported operand type(s) for item assignment: bool [unsupported-operands]
      No attribute '__setitem__' on bool
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 260, in _graft_revisions: unsupported operand type(s) for item assignment: bytes [unsupported-operands]
      No attribute '__setitem__' on bytes
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 270, in _graft_revisions: No attribute 'get' on bool [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 270, in _graft_revisions: No attribute 'get' on bytes [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 280, in _graft_revisions: No attribute 'get' on bool [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft
    File "/mnt/c/Users/Matt/hg/mercurial/cmd_impls/graft.py", line 280, in _graft_revisions: No attribute 'get' on bytes [attribute-error]
      In Union[Any, Callable, Dict[bytes, Optional[Any]], bool, bytes, dict]
    Called from (traceback):
      line 21, in cmd_graft

mercurial/cmd_impls/graft.py

@@ -2,12 +2,24
 
 from __future__ import annotations
 
+import typing
+
+from typing import (
+    Any,
+    Tuple,
+)
+
 from ..i18n import _
 
 from .. import cmdutil, error, logcmdutil, merge as mergemod, state as statemod
 
 
-def cmd_graft(ui, repo, *revs, **opts):
+if typing.TYPE_CHECKING:
+    _ActionT = str
+    _CmdArgsT = Any  # TODO: (statedata, revs, editor, cont, dry_run, tool)
+
+
+def cmd_graft(ui, repo, *revs, **opts) -> int:
     """implement the graft command as defined in mercurial/commands.py"""
     ret = _process_args(ui, repo, *revs, **opts)
     action, graftstate, args = ret
@@ -25,7 +37,9 def cmd_graft(ui, repo, *revs, **opts):
         raise error.ProgrammingError('unknown action: %s' % action)
 
 
-def _process_args(ui, repo, *revs, **opts):
+def _process_args(
+    ui, repo, *revs, **opts
+) -> Tuple[_ActionT, statemod.cmdstate | None, _CmdArgsT | None]:
     """process the graft command argument to figure out what to do
 
     This also filter the selected revision to skip the one that cannot be graft