Markdown Filter: Support backslash escapes

[Chase Tingley]

Reference: https://spec.commonmark.org/0.28/#backslash-escapes

This isn’t that widely used, but we don’t support it on either extraction or merge. This should be controlled by at least one config option (possibly two).

[Alec Shashaty]

We can close this I believe.

[Chase Tingley]

Fixed by https://bitbucket.org/okapiframework/okapi/pull-requests/553