Add MSBuild language based on XML grammar

[brettlyons]

Filetype reference: https://stackoverflow.com/questions/2007689/is-there-a-standard-file-extension-for-msbuild-files

#5754

[the-mikedavis]

In order to add syntax highlighting, you will need to create some files in runtime/queries/msbuild/: highlights.scm, injections.scm and indents.scm. All of these should just have the contents

; inherits: xml

That will re-use the XML tree-sitter queries for syntax highlighting and indentation.

Also, you will need to run cargo xtask docgen and commit the changes to add msbuild support to the documentation. (This will fix the CI.)

[the-mikedavis]

Thanks!