False negative: Not flagging "your" when it should be "you're"

My brain must be rotting. I wrote "your" in a reply to a user question where it should be "you're" but only noticed the next day. Harper does not catch it:

> Something else? I'm not sure how your using it.

Note that verbs in the `-ing` form are grammatical after both "your" and "you're". After "your" it would be a gerund, so acting as a noun. After "you're" it would be a present participle, so acting as part of the verb phrase together with the "are" that's contracted onto "you". Would need a deeper heuristic.

No source file, test, or entry point is identified in the issue. Begin by reproducing the quoted sentence in Harper and investigate how it distinguishes “your” from “you’re” before the following -ing form; done means catching this example while preserving the grammatical “your” case.

Written by the indexing model from the issue text.