Release Notes:
- "Block" diagnostics (that show up in the diagnostics view, or when
using `f8`/`shift-f8`) are rendered more clearly
- `f8`/`shift-f8` now always go to the "next" or "prev" diagnostic,
regardless of the state of the editor

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Co-authored-by: Kirill Bulatov <mail4score@gmail.com>
Co-authored-by: Julia Ryan <juliaryan3.14@gmail.com>