http: improve types

[JelleZijlstra]

No description provided.

[srittau]

HTTPConnection.send() also allows str:

    def request(self, method, url, body=None, headers={}, *,
                encode_chunked=False):
        """Send a complete request to the server."""
        self._send_request(method, url, body, headers, encode_chunked)

    def _send_request(self, method, url, body, headers, encode_chunked):
        # ...
        # It also gets passed to _get_content_length(), which also supports str
        # ...

        if isinstance(body, str):
            # RFC 2616 Section 3.7.1 says that text default has a
            # default charset of iso-8859-1.
            body = _encode(body, 'body')
        self.endheaders(body, encode_chunked=encode_chunked)

I think the best solution is just to add str to the body argument of request manually.

[srittau]

As directory is keyword only and I can't find index_pages anywhere (on 3.9):

Suggested change

	server: socketserver.BaseServer,
	directory: str | None = ...,
	index_pages: Sequence[str] | None = ...,
	server: socketserver.BaseServer,
	*,
	directory: str | None = ...,

(directory is also passed to os.fspath() in later version (but not 3.7), but that's out of scope for this PR, since it needs overloads.)

[AlexWaygood]

index_pages is new in 3.12: python/cpython#31985. So we should branch on if sys.version_info >= (3, 12).

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉