Some editors use diagnostics from SourceKit to replace build issues. This causes issues if the diagnostics from SourceKit are formatted differently than the build issues. Make sure they are rendered the same way, removing most uses of `DiagnosticsEditorMode`.
To do so, always emit the `add stubs for conformance` note (which previously was only emitted in editor mode) and remove all `; add <something>` suffixes from notes that state which requirements are missing.
rdar://129283608
I'm not really convinced that this shouldn't be done by introducing a new
kind of constraint rather than hacking in what are essentially conversions
as "bind" constraints, but this is the most direct path for now.
Fixes rdar://125394096