R1:dba1b1072033

Deactivate the remarkup autosuggest once text can't match "[[" or "((" rules

Summary:
See PHI1185, which reports a performance issue with "(" in remarkup in certain contexts.

I can't reproduce the performance issue, but I can reproduce the autosuggester incorrectly remaining active and swallowing return characters.

When the user types `(` or `[`, we wait for a prefix for the `((` (Phurl) or `[[` (Phriction) rules. We currently continue looking for that prefix until a character is entered that explicitly…