[llvm] [clang-doc] fix mustache template whitespace (PR #153724)

[via llvm-commits]

mdenson wrote:

Sorry I'm new here and still getting familiar with the project. I thought the unit tests at https://github.com/llvm/llvm-project/blob/main/llvm/unittests/Support/MustacheTest.cpp were meant to test conformance. Although I see now that there are tests from https://github.com/mustache/spec v1.4.3 that are missing.

> We have an in-tree tool to test the conformance

How is this tool different, and when should I use one over the other?

> My intuition is that the whitespace issue you're fixing on the clang-doc side is a symptom of this deficiency in our mustache implementation.

Ah, then perhaps I've really misunderstood this one. I thought llvm/lib/Support/Mustache.cpp was 'our mustache implementation'? Where should I be looking to sort that out?

> That may be true, but clang-doc is supposed to be a standalone tool with no external dependencies. You're right that another library or external tool may be even more well suited to the task, but its our goal to provide a compelling implementation here, and to not require any other third-party dependencies. We're just not quite there yet.

I figured this was the case. Understood.

https://github.com/llvm/llvm-project/pull/153724