A line in the title blacklist can contains pipe as part of a regex,
the pipe is also used in wikitext, so it needs escaping to allow use of
templates in system message.
Bug: T350296
Change-Id: I7f18bb7111b989cc66808f17476bacdf45120e09
E.g. reducing deep indention and code duplication. Removing comments
that literally repeat what the code says.
The goal is to make the code easier to read and to maintain in the
future. I hope this is the case.
Change-Id: I6f23bc61ffb8b6d42ec697fec91bb6c92152561f
