When testing the configuration binder source generator we discovered that the way the runtime source generators emit diagnostics is not suppressible in source. This is a regression from previous releases (see attached sample) however we've yet to scenario where a user would have a pragma suppression for one of these existing diagnostics - most are errors or informational.

See attached project: generatorWarnings.zip

We also discovered that even in previous releases, when a warning is praga suppressed the IDE analyzer flags the suppression as unnecessary.

We also discovered that in 8.0, the diagnostics (at least in Regex generator) no longer seem to honor .editorconfig severity setting.

Related: dotnet/roslyn#68291

CC @eiriktsarpalis, @stephentoub