Rollup merge of #129086 - slanterns:is_none_or, r=dtolnay

Stabilize `is_none_or`

Closes: rust-lang/rust#126383.

`@rustbot` label: +T-libs-api

r? libs-api

Author: matthiaskrgr

src/lib.rs

@@ -12,7 +12,6 @@
 #![feature(let_chains)]
 #![feature(trait_upcasting)]
 #![feature(strict_overflow_ops)]
-#![feature(is_none_or)]
 // Configure clippy and other lints
 #![allow(
     clippy::collapsible_else_if,