[clang] [WebAssembly] Enable multivalue and reference-types in generic CPU config (PR #80923)

[Alon Zakai via cfe-commits]

================
@@ -668,6 +668,11 @@ AIX Support
 WebAssembly Support
 ^^^^^^^^^^^^^^^^^^^
 
+The -mcpu=generic configuration now enables multivalue and reference-types.These
+proposals are standardized and available in all major engines. Enabling
+multivalue here only enables the language feature but does not turn on the
+multivalue ABI.
----------------
kripken wrote:

Maybe worth adding something like this:
```suggestion
multivalue ABI (this enables non-ABI uses of multivalue, like exnref).
```

https://github.com/llvm/llvm-project/pull/80923