[clang] [clang] Be const-correct with all uses of `Module *`. (PR #93493)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> `const_cast` here is a relatively recent addition, and I checked out with @erichkeane that the use case (pack expansion) is legit. According to the approach you're suggesting, the one who wrote this `const_cast` should instead refactor the MLTAL to use `llvm::MutableArrayRef`.

Take a guess who that person was :grin:

> I tried, pretty hard, but ultimately failed. The change turned out to be touching every corner of our template engine, with no end in sight.

Oh well, sorry I wasn't around to advise against it.


https://github.com/llvm/llvm-project/pull/93493