Source Link fails due to wrong filename casing

Debugging into WPF’s source code fails for some files due to wrong/mismatched filename casing. For example debugging into the source for ToolTip yields:

ToolTip.cs not found: Source Link authentication failed

You need to find ToolTip.cs to view the source for the current call stack frame

Source Link Error:
git-credential-manager-core.exe: Could not obtain credentials. Process failed with exit code -1.
ERROR: The request failed with code 404 : "Not Found". Treating 404 as authentication failure. Some services return 404 instead of 401 for authentication failures.

Source Link URL: https://raw.githubusercontent.com/dotnet/wpf/dabcf2041548f7594b21e9bf865463abdfd14307/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/ToolTip.cs

Note that the embedded URL uses ToolTip.cs (because PresentationFramework.csproj specifies <Compile Include="System\Windows\Controls\ToolTip.cs" />). But the file in the repository is named tooltip.cs (all lowercase), and such GitHub-URLs are case-sensitive.

There may be more files that have the wrong casing (I haven’t checked).

[ThomasGoulet73]

I made a quick tool to check if the casing of the file in the csproj is the same as in the file system or if multiple projects reference the same files with different casing and I found more files with the wrong casing. I opened #6762 which fixes casing for more files.

[dipeshmsft]

@gix @lindexi There may be some other files that may have the same issue. I think we can go ahead and fix them along with this PR.