[clang] Revise the modules document for clarity (PR #90237)

[Vlad Serebrennikov via cfe-commits]

================
@@ -432,9 +424,8 @@ The following example is not allowed:
   $ clang++ -std=c++20 M.cppm --precompile -o M.pcm
   $ clang++ -std=c++23 Use.cpp -fprebuilt-module-path=.
 
-The compiler would reject the example due to the inconsistent language options.
-Not all options are language options.
-For example, the following example is allowed:
+Clang rejects the example due to the inconsistent language standard modes. Not
+all compiler options are language dialect options. For example:
----------------
Endilll wrote:

```suggestion
all compiler options are language dialect options, though. For example:
```

https://github.com/llvm/llvm-project/pull/90237