Add support for wix files

[Kvan7]

Adds commonly used wix file extensions: wixproj, wxs, wxi, wxl

Wix is a toolset for creating msi installers, https://github.com/wixtoolset/wix

[Kvan7]

I couldn't find great docs newer versions of wix, but the file extensions have stayed the same from what I can tell.
(also not an expert in wix)
https://docs.firegiant.com/wix3/overview/files/
there are also some linking/output files but I didn't include them in this since I have never touched them myself & they have less than 50 results when searching the file types on github

[asottile]

I feel like these shouldn't all have the same tag since semantically the extensions mean different things?

[Kvan7]

I had just done them all with the same since they were related & to group them. I don't really have much preference though so I can change them to be individual if that matches the convention other files use better

[asottile]