Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`
Part of https://github.com/element-hq/synapse/issues/18905
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
The callers either set a default limit or manually handle a None-limit
later on (by setting a default value).
Update the callers to always instantiate PaginationConfig with a default
limit and then assume the limit is non-None.
* Remove unused mocks from `test_typing`
It's not clear what these do. `get_user_by_access_token` has the wrong
signature, including the return type. Tests all pass without these. I
think we should nuke them.
* Changelog
* Fixup imports
* Add type hints to `tests/rest/client`
* newsfile
* fix imports
* add `test_account.py`
* Remove one type hint in `test_report_event.py`
* change `on_create_room` to `async`
* update new functions in `test_third_party_rules.py`
* Add `test_filter.py`
* add `test_rooms.py`
* change to `assertEquals` to `assertEqual`
* lint
