Update 'WinFx' -> 'WinFX' casing

[Nirmal4G]

As the title suggests, This PR renames WinFx to WinFX where possible.

I've separated out the white-space changes to a separate commit.
Only files that were touched with WinFX casing changes are updated with formatting changes.
If it's not possible to merge and/or if you want the line & space changes applied to the whole repo, please let me know, I'll separate these into a new PR.

Related: dotnet/wpf#2975

The casing could also be updated for WPF (.NET Framework) targets and sources.

[rainersigwald]

Since Microsoft.WinFx.targets shipped with .NET Framework and is unlikely to be renamed/recase, I think we should match its shipped on-disk case, and propagate that case to our local shim copy. As a result, I don't think we should take this PR (even though the casing you propose is better to my eyes, too).

[Nirmal4G]

@rainersigwald

even though the casing you propose

I'm not proposing a new case change. NETCLR 2 msbuild tools shipped with WinFX correct casing. Somehow NETCLR 4 has changed the case into WinFx. I suspect automated tools.

I don't think we should take this PR

These targets still have the correct casing though!

msbuild/src/Tasks/Microsoft.NETFramework.CurrentVersion.targets

Line 129 in 26f6d1d

<Import Project="$(MSBuildToolsPath)\Microsoft.WinFX.targets" Condition="'$(TargetFrameworkVersion)' != 'v2.0' and '$(TargetCompactFramework)' != 'true' and Exists('$(MSBuildToolsPath)\Microsoft.WinFX.targets')"/>

msbuild/src/Tasks/Microsoft.Common.CurrentVersion.targets

Line 6151 in 26f6d1d

<Import Project="$(MSBuildToolsPath)\Microsoft.WinFX.targets" Condition="'$(TargetFrameworkIdentifier)' == 'Silverlight' and Exists('$(MSBuildToolsPath)\Microsoft.WinFX.targets')"/>

.NET Framework is Windows only and Case in-sensitive. Even though .NET Framework has high bar for compat, this doesn't seem to be a breaking change. This PR just matches them. I think It's OK to merge though.

So, Can I ask Why?

[rainersigwald]

I don't know why it changed from .NET 3.5 to .NET 4.something. I agree that it shouldn't have--but at this point changing it back is not worth much and might break someone.

I took a look around and this file is present in Mono installs on macOS (at least), so it can be present on a case-sensitive filesystem. Combined with the low impact of the change I don't think we should take this.

Thanks for trying to clean this up!