Dismiss the hint on a non-word-starting non-separator

This would happen when a character is not a separator but is not
a word starter. Such characters include single quote and
dollar, and others non-letter, non-separator chars.
We set the bigram predictions if any - if not so configured, this
will fallback on setting back punctuations into the strip.

Bug: 6010408
Change-Id: Id203bbe87f8c13de0d5027b555c9067c7ec98f92