Include slide and notes location in find_in_document results for decks

[ilia-sokolov]

Problem you're trying to solve

#9 added location to FindHit for Word, so find_in_document and inspect_document now agree about where matched text lives. The same disagreement remains for PowerPoint.

Proposed shape

Thread the paragraph's location into AddHit, mirroring the Word change in #9. Both call sites in PowerPointModule.Find already have paragraph in scope, so the value is paragraph.Location.
For a deck the values are slide and notes.

[aryansk]

I’m planning the focused PowerPoint parity fix: thread paragraph.Location into FindHit and add slide/notes assertions so callers can distinguish where each match came from.