typing: make the manifest classes known to pytype

These are the same changes as c1d7ac70980b and 45270e286bdc made to dirstate,
for the same reasons.  The migration away from decorating the classes with
`@interfaceutil.implementer` was started back in 3e9a660b074a, but missed one.

mercurial/manifest.py

@@ -9,6 +9,7
 import heapq
 import itertools
 import struct
+import typing
 import weakref
 
 from typing import (
@@ -753,6 +754,9 class ManifestDict:
 
 manifestdict = interfaceutil.implementer(repository.imanifestdict)(ManifestDict)
 
+if typing.TYPE_CHECKING:
+    manifestdict = ManifestDict
+
 
 def _msearch(
     m: ByteString, s: bytes, lo: int = 0, hi: Optional[int] = None
@@ -1535,6 +1539,9 class TreeManifest:
 
 treemanifest = interfaceutil.implementer(repository.imanifestdict)(TreeManifest)
 
+if typing.TYPE_CHECKING:
+    treemanifest = TreeManifest
+
 
 class manifestfulltextcache(util.lrucachedict):
     """File-backed LRU cache for the manifest cache
@@ -2047,13 +2054,14 manifestrevlog = interfaceutil.implement
     ManifestRevlog
 )
 
+if typing.TYPE_CHECKING:
+    manifestrevlog = ManifestRevlog
 
 AnyManifestCtx = Union['ManifestCtx', 'TreeManifestCtx']
 AnyManifestDict = Union[ManifestDict, TreeManifest]
 
 
[e-mail](repository.imanifestlog)
-class manifestlog:
+class ManifestLog:
     """A collection class representing the collection of manifest snapshots
     referenced by commits in the repository.
 
@@ -2157,6 +2165,12 class manifestlog:
         return self._rootstore._revlog.update_caches(transaction=transaction)
 
 
+manifestlog = interfaceutil.implementer(repository.imanifestlog)(ManifestLog)
+
+if typing.TYPE_CHECKING:
+    manifestlog = ManifestLog
+
+
 class MemManifestCtx:
     def __init__(self, manifestlog):
         self._manifestlog = manifestlog
@@ -2190,6 +2204,9 memmanifestctx = interfaceutil.implement
     repository.imanifestrevisionwritable
 )(MemManifestCtx)
 
+if typing.TYPE_CHECKING:
+    memmanifestctx = MemManifestCtx
+
 
 class ManifestCtx:
     """A class representing a single revision of a manifest, including its
@@ -2353,6 +2370,9 manifestctx = interfaceutil.implementer(
     ManifestCtx
 )
 
+if typing.TYPE_CHECKING:
+    manifestctx = ManifestCtx
+
 
 class MemTreeManifestCtx:
     def __init__(self, manifestlog, dir=b''):
@@ -2392,6 +2412,9 memtreemanifestctx = interfaceutil.imple
     repository.imanifestrevisionwritable
 )(MemTreeManifestCtx)
 
+if typing.TYPE_CHECKING:
+    memtreemanifestctx = MemTreeManifestCtx
+
 
 class TreeManifestCtx:
     def __init__(self, manifestlog, dir, node):
@@ -2660,6 +2683,9 treemanifestctx = interfaceutil.implemen
     TreeManifestCtx
 )
 
+if typing.TYPE_CHECKING:
+    treemanifestctx = TreeManifestCtx
+
 
 class excludeddir(treemanifest):
     """Stand-in for a directory that is excluded from the repository.