Auto merge of #114656 - bossmc:rework-no-coverage-attr, r=oli-obk

Rework `no_coverage` to `coverage(off)`

As discussed at the tail of https://github.com/rust-lang/rust/issues/84605 this replaces the `no_coverage` attribute with a `coverage` attribute that takes sub-parameters (currently `off` and `on`) to control the coverage instrumentation.

Allows future-proofing for things like `coverage(off, reason="Tested live", issue="#12345")` or similar.

compiler/rustc_span/src/symbol.rs

@@ -574,6 +574,8 @@ symbols! {
         cosf32,
         cosf64,
         count,
+        coverage,
+        coverage_attribute,
         cr,
         crate_id,
         crate_in_paths,
@@ -1069,6 +1071,7 @@ symbols! {
         note,
         object_safe_for_dispatch,
         of,
+        off,
         offset,
         offset_of,
         omit_gdb_pretty_printer_section,