PublicAPIAnalyzer CodeFix does not respect existing newline style

[333fred]

roslyn-analyzers/src/PublicApiAnalyzers/Core/CodeFixes/DeclarePublicApiFix.cs

Line 110 in 62f71ea

var newText = string.Join(Environment.NewLine, lines) + GetEndOfFileText(sourceText);

Instead of reading the line endings that already exist in the file, the public API analyzers use the default from the environment. This is a problem on Windows when autocrlf is off, or when the source is shared with a Linux partition (such as WSL or when running Windows in a VM) and the line endings are set to just \n. Instead, it should be looking at the existing line endings in the file and, if they are just \n, only using that, instead of unconditionally using the environment-default newline.

[Youssef1313]

The same should apply to AnnotatePublicApiFix and NullableEnablePublicApiFix.