Rollup merge of #153335 - Ozzy1423:removed-features, r=jdonszelmann

Add #![unstable_removed(..)] attribute to track removed features

Adds the #![unstable_removed(..)] attribute to enable tracking removed library features.
Produce an error when a removed attribute is used.
Add a test that it works.

For rust-lang/rust#141617

r? @jyn514

Author: JonathanBrouwer