auto merge of #16433 : aturon/rust/deprecated-in-crate, r=alexcrichton

Previously the stability lint considered cross-crate items only. That's appropriate for unstable and experimental levels, but not for deprecation.

In addition to changing the lint, this PR takes care of the fallout: a number of deprecated items that were being used throughout libstd.

Closes #16409

Due to deny(deprecated), this is a:

[breaking-change]