Re-add #![feature(target_feature_11)]

taiki-e · Amanieu · commit dbc5f5108fb8 · 2023-03-05T17:02:26.000+01:00
We removed this in 307c42f, but the stabilization was reverted in rust-lang#108654.
diff --git a/stdarch/crates/core_arch/src/lib.rs b/stdarch/crates/core_arch/src/lib.rs
@@ -30,6 +30,7 @@
     allow_internal_unstable,
     decl_macro,
     asm_const,
+    target_feature_11,
     inline_const,
     generic_arg_infer
 )]
