Rollup merge of rust-lang#93745 - tarcieri:stabilize-adx, r=cjgillot

Stabilize ADX target feature

This is a continuation of rust-lang#60109, which noted that while the ADX intrinsics were stabilized, the corresponding target feature never was.

This PR follows the same general structure and stabilizes the ADX target feature.

See also rust-lang#44839 - tracking issue for target feature

Author: Dylan-DPC

core/src/lib.rs

@@ -207,7 +207,6 @@
 //
 // Target features:
 #![cfg_attr(bootstrap, feature(aarch64_target_feature))]
-#![feature(adx_target_feature)]
 #![feature(arm_target_feature)]
 #![feature(avx512_target_feature)]
 #![feature(cmpxchg16b_target_feature)]
@@ -219,6 +218,7 @@
 #![feature(sse4a_target_feature)]
 #![feature(tbm_target_feature)]
 #![feature(wasm_target_feature)]
+#![cfg_attr(bootstrap, feature(adx_target_feature))]
 
 // allow using `core::` in intra-doc links
 #[allow(unused_extern_crates)]