Rollup merge of #151919 - JayanAXHF:fix_color_always, r=nnethercote

fix: Make `--color always` always print color with `--explain`

Fixes rust-lang/rust#151643.

This changes the behaviour of `handle_explain` in `rustc_driver_impl` to always output color when the `--color always` flag is set.

r? @tgross35

Author: Zalathar