False negative in `SplitWords` with "titlecase" only flagged by spellchecker so "title case" not suggested

**Describe the bug**

The word "titlecase" is not in the dictionary so Harper flags it. That's fine. But the spellchecker only suggests "telecast", "titles", and "title's" as corrections. We have another linter, `SplitWords` that ought to also flag it but suggest "title case". But this does not happen.

I suspect this may be due to `remove_overlaps()` and perhaps to the `priority` field of `Lint`?

Both linters should get a say on the suggestions.

**Screenshots**

"titlecase" not suggested to split into "title case":

**Platform**
Google Chrome plugin.

Start by tracing the SplitWords result for “titlecase” through remove_overlaps() and inspect how the priority field of Lint affects competing suggestions. Confirm that the spellchecker and SplitWords results are both available, then verify that the final suggestions include “title case” in the Chrome plugin.

Written by the indexing model from the issue text.