Analyzer

Diagnostic ID: RS0016

Describe the improvement

Currently the RS0016 fixer creates new PublicApi.*.txt files without #nullable enable. This rather frequently leads to RS0037 warnings i.e. the RS0016 is not generating useful / valid API baseline files.

Describe suggestions on how to achieve the rule

Either the analyzer should always reflect whatever nullability attributes appear in the assembly or the fixer should detect the presence of some of these attributes and include #nullable enable when creating API baselines.

Additional context

See also #3957.