[DOCS] Build Reference update to use the LLVM linker

[lemonade-dm]

Describe the issue briefly

There is a change in the o3de repo to add support for using the LLVM linker by default. With that change, there is an addition of a CMake Cache Variable called LY_LINKER that allows the user to force set a linker to use when the clang compiler is being used

Which page(s) / section(s) are affected?

The page that would need to be updated is this page.

Does this work have an engineering dependency? What is it?

The PR for this change is at https://github.com/o3de/o3de/pull/16101#discussion_r1218541863

[nicholas-rh]

Opened a PR here #2427