R1:6dea2ba3b37f

Fix DocumentEngine line behaviors in Diffusion

Summary:
Ref T13105. Fixes some issues with line linking and highlighting under DocumentEngine:

- Adding `$1-3` to the URI didn't work correctly with query parameters.
- Reading `$1-3` from the URI didn't work correctly because Diffusion parses them slightly abnormally.

Test Plan: Clicked/dragged lines to select them. Observed URI. Reloaded page, got the right selection.

Reviewers: mydeveloperday

Reviewed By: mydeveloperday

Maniphest Tasks: T13105…