Parse the message in html according to the errorformat= in the url,
fallback to wikitext to avoid a breaking change.
Bug: T369244
Change-Id: I58b995b3663b7dd286267e640d8d56164bd9be0b
titleblacklist is not part of action=query (since a2f5ccd2 back in 2011)
and should not follow that naming schema.
No class alias as nobody needs to call the class directly
Change-Id: If57e5bd9291a894edf42835fed07d37cd8e8abed
When the custom error message contains {{PAGENAME}} or other title based
variables, there are currently parsed as
"Badtitle/dummy_title_for_API_calls_set_in_api.php"
The same custom message is shown correctly on index.php
Bug: T340923
Change-Id: I4c1dc6660976de54ff6ba8f8f7a5768371e61e80
