Revert "Auto merge of #130766 - clarfonthey:stable-coverage-attribute, r=wesleywiser"

This reverts commit 1d35638dc38dbfbf1cc2a9823135dfcf3c650169, reversing
changes made to f23a80a4c2fbca593b64e70f5970368824b4c5e9.

Author: Zalathar

crates/hir-expand/src/inert_attr_macro.rs

@@ -237,7 +237,7 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
         template!(List: "address, kcfi, memory, thread"), DuplicatesOk,
         experimental!(no_sanitize)
     ),
-    ungated!(coverage, Normal, template!(Word, List: "on|off"), WarnFollowing),
+    gated!(coverage, Normal, template!(Word, List: "on|off"), WarnFollowing, coverage_attribute, experimental!(coverage)),
 
     ungated!(
         doc, Normal, template!(List: "hidden|inline|...", NameValueStr: "string"), DuplicatesOk