Rework editors to register and query buffers on scroll (#40388)
Preparation to https://github.com/zed-industries/zed/pull/40183
Moves https://github.com/zed-industries/zed/pull/22958 further: now,
instead of selection, scrolling the buffer into view is enough to get
registered and, later, be queried for its LSP data such as inlay hints,
diagnostics and document colors.
This effectively undoes https://github.com/zed-industries/zed/pull/28855
as now we try to register whatever's visible more aggressively, instead
of implicitly via inlay hints.
Release Notes:
- Reworked editors to register and query buffers on scroll
de8dd9bea5