Module documentation improvement: prebuilt module location can be directly...

Module documentation improvement: prebuilt module location can be directly fetched via CMake variable. (#78405)

CMake officially supports binary directory variable of installed
dependency using `FetchContent`. According to the current documentation,
it fetches `std` module and use its binary directory as hardcoded
string, `${CMAKE_BINARY_DIR}/_deps/std-build`, however it can be
replaced with `${std_BINARY_DIR}`.

Reference: https://cmake.org/cmake/help/latest/module/FetchContent.html