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
This commit changes fixit messages from a question/suggestion to an
imperative message for protocol conformances and switch-case. Addresses
https://github.com/apple/swift/issues/67510.
We can't assume that we will always find a viable witness for a protocol
requirement when typechecking a `.swiftinterface` file. The assert that assumed
there would be a match could fail when building a broken interface or building
a valid interface with a broken SDK, causing crashes instead of emitting
diagnostics.
Resolves rdar://108688535
