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

[via cfe-commits]

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@@ -577,15 +574,16 @@ the generated BMI specified by ``-o`` will be full BMI and the BMI specified by
                                                -> ...
                                                -> consumer_n.cpp
 
-We don't emit diagnostics if ``-fexperimental-modules-reduced-bmi`` is used with a non-module
-unit. This design helps the end users of one phase compilation model to perform experiments
-early without asking for the help of build systems. The users of build systems which supports
-two phase compilation model still need helps from build systems.
+Clang does not emit diagnostics when ``-fexperimental-modules-reduced-bmi`` is
+used with a non-module unit. This design helps the end users of the one-phase
+compilation model to perform experiments without needing to modify the build
+system. The two-phase compilation module requires build system support.
 
-Within Reduced BMI, we won't write unreachable entities from GMF, definitions of non-inline
-functions and non-inline variables. This may not be a transparent change.
-`[module.global.frag]ex2 <https://eel.is/c++draft/module.global.frag#example-2>`_ may be a good
-example:
+In a Reduced BMI, Clang does not emit unreachable entities from the global
+module fragment, or definitions of non-inline functions and non-inline
+variables. This may not be a transparent change.
+
+[module.global.frag]ex2 provides a good example:
----------------
cor3ntin wrote:

The specific c++ standard reference isn't useful. Just "consider the following example"

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