[libcxx-commits] [libcxx] [libcxx][docs] Make test name pattern documentation more obvious (PR #73136)

[Will Hawkins via libcxx-commits]

hawkinsw wrote:

> > The other thing that I would like to add with this PR is documentation on the actual commands available in the lit built-in shell tests.
> 
> Which commands do you mean? The actual builtin Lit ShTest commands like `RUN`? If so, those are already documented in Lit-specific documentation. We should move the documentation for the commands we add in our test format (like `ADDITIONAL_COMPILE_FLAGS`), though.

Great! I will work on that. 

I was talking about documenting the builtin lit "shell" commands (e.g., 

```Python
    inproc_builtins = {
        "cd": executeBuiltinCd,
        "export": executeBuiltinExport,
        "echo": executeBuiltinEcho,
        "@echo": executeBuiltinEcho,
        "mkdir": executeBuiltinMkdir,
        "popd": executeBuiltinPopd,
        "pushd": executeBuiltinPushd,
        "rm": executeBuiltinRm,
        ":": executeBuiltinColon,
    }   
```

and if/how they differ in their meaning from posix (or PowerShell). Those are not documented in the other lit documentation (e.g., https://llvm.org/docs/TestingGuide.html#writing-new-regression-tests) and it was something that I struggled to find. Would you prefer that I send that as PR directly to lit?

I will reflag you for a review when it is ready! Thanks again!

https://github.com/llvm/llvm-project/pull/73136