Reconsider using the incorrectly cased input file name for TranslatedFile

[PathogenDavid]

Currently if the user provides the incorrect casing for a file name, we prefer using their casing:

https://github.com/InfectedLibraries/Biohazrd/blob/23589dbdba1590a863097eba071bb0f5c7919df0/Biohazrd/TranslationUnitParser.cs#L131-L136

Upon a second look, I'm not sure this is a great idea. Instead we should prefer the real casing provided by Clang and warn if the provided casing was different.

However, this isn't ideal if Clang can't provide the real casing. (When does TryGetRealPathName fail?) Because then we're using the (possibly incorrect) casing from an #include directive.

https://github.com/InfectedLibraries/Biohazrd/blob/23589dbdba1590a863097eba071bb0f5c7919df0/Biohazrd/TranslationUnitParser.cs#L113-L114

(I think this code was written this was for that reason before I found TryGetRealPathName.)

Perhaps the ideal solution is:

• Use the Clang real path casing
• If that casing differs from what we were given, emit a warning since the generator isn't portable
• Emit a warning if Clang doesn't provide the real casing (Assuming that situation is uncommon/rare -- need to investigate.)