* Unpin Twisted, add a twisted-trunk tox env (without http2 for now).
* Hide the _setAcceptableProtocols import.
* Silence ScrapyClientContextFactory HTTP/1.0 warnings.
* Update ScrapyClientTLSOptions for unreleased Twisted.
* Add twisted-trunk to CI.
* Update for new changes in Twisted trunk.
* Xfail a test failing with newer Twisted.
* Test Twisted trunk with extra-deps, update the ALPN code.
* Cleanup.
* Fix typing.
* Update relevant type hints for Twisted trunk.
* Update test_no_context_sharing().
* Silence a weird mypy error.
* Update Twisted versions, unpin pyOpenSSL.
* Update a comment.
* Silence pylint.
* Make a factory fixture.
* Improve the _setAcceptableProtocols comment.
* Set OP_LEGACY_SERVER_CONNECT on new Twisted too.
* Add Twisted[http2] to extra-deps-pinned.
* Use AsyncCrawlerProcess if TWISTED_REACTOR_ENABLED=False.
* defer.Deferred -> Deferred.
* Allow Shell with TWISTED_REACTOR_ENABLED=False.
* Shell workflow notes.
* Remove an unused argument.
* Shell.fetch_available.
* Shell._use_reactor.
* Some more comments.
* Simplify _schedule() and fix the spider shell var.
* More async def.
* Reactorless shell support.
* Add pragma: no cover.
* More notes.
* Remove a TODO.
* Add a crawler argument to MiddlewareManager.__init__().
* Deprecate the spider argument in some MiddlewareManager subclasses.
* Remove the spider argument from ExecutionEngine.open_spider_async().
* Remove the spider argument from Scraper.open_spider().
* Fix the Scraper.close_spider() type hint.
* Remove the spider argument from Downloader internals.
* Deprecate the spider arg of download_func.
* Deprecate the spider arg of Downloader.fetch().
* Deprecate the spider arg of ItemPipelineManager.process_item().
* Fix pylint.
* Tests for MiddlewareManager spider code.
* Deprecated spider arg handling for custom pipeline managers.
* Add a test for the deprecated spider arg in a custom downloader.
* Remove TODO.
* Fix pylint.