[clang-tools-extra] [llvm] [llvm] add support for mustache templating language (PR #105893)

[Paul Kirth via llvm-commits]

ilovepi wrote:

@PeterChou1 It's been a few weeks since we've seen progress here. Is this something you're planning to finish out? or should @petrhosek or I should dedicate some effort into getting landed? The Clang-Doc refactor to use the templates is going to be hard to review until this is in, and I'd very much like to see all your work in tree as soon as possible. Mostly, because we want to start using it.

https://github.com/llvm/llvm-project/pull/105893