http2: remove non-existent pushStream weight option
The PRIORITY field is only supported by HTTP/2 in a HEADERS frame initiated by the client, not in a push request sent by the server.
Documents the recommended approach to set a silent priority as used internally by nghttp2.
Alternative to #16444
Checklist
-
documentation is changed or added -
commit message follows commit guidelines
Affected core subsystem(s)
http2