Add missing type hints to non-client REST servlets. (#10817)

Including admin, consent, key, synapse, and media. All REST servlets
(the synapse.rest module) now require typed method definitions.

synapse/rest/media/v1/media_storage.py

@@ -15,7 +15,20 @@ import contextlib
 import logging
 import os
 import shutil
-from typing import IO, TYPE_CHECKING, Any, Callable, Optional, Sequence
+from types import TracebackType
+from typing import (
+    IO,
+    TYPE_CHECKING,
+    Any,
+    Awaitable,
+    BinaryIO,
+    Callable,
+    Generator,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+)
 
 import attr
 
@@ -83,12 +96,14 @@ class MediaStorage:
 
         return fname
 
-    async def write_to_file(self, source: IO, output: IO):
+    async def write_to_file(self, source: IO, output: IO) -> None:
         """Asynchronously write the `source` to `output`."""
         await defer_to_thread(self.reactor, _write_file_synchronously, source, output)
 
     @contextlib.contextmanager
-    def store_into_file(self, file_info: FileInfo):
+    def store_into_file(
+        self, file_info: FileInfo
+    ) -> Generator[Tuple[BinaryIO, str, Callable[[], Awaitable[None]]], None, None]:
         """Context manager used to get a file like object to write into, as
         described by file_info.
 
@@ -125,7 +140,7 @@ class MediaStorage:
         try:
             with open(fname, "wb") as f:
 
-                async def finish():
+                async def finish() -> None:
                     # Ensure that all writes have been flushed and close the
                     # file.
                     f.flush()
@@ -315,7 +330,12 @@ class FileResponder(Responder):
             FileSender().beginFileTransfer(self.open_file, consumer)
         )
 
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
         self.open_file.close()
 
 
@@ -339,7 +359,7 @@ class ReadableFileWrapper:
     clock = attr.ib(type=Clock)
     path = attr.ib(type=str)
 
-    async def write_chunks_to(self, callback: Callable[[bytes], None]):
+    async def write_chunks_to(self, callback: Callable[[bytes], None]) -> None:
         """Reads the file in chunks and calls the callback with each chunk."""
 
         with open(self.path, "rb") as file: