Auto merge of #115286 - saethlin:detangler, r=petrochenkov

Skip rendering metadata strings from include_str!/include_bytes!

The const rendering code in rustdoc completely ignores consts from expansions, but the compiler was rendering all consts. So some consts (namely those from `include_bytes!`) were rendered then ignored.

Most of the diff here is from moving `print_const_expr` from rustdoc into `rustc_hir_pretty` so that it can be used in rustdoc and when building rmeta files.

Author: bors