Rename HandlerInner::delay_span_bug as HandlerInner::span_delayed_bug.

Because the corresponding `Level` is `DelayedBug` and `span_delayed_bug`
follows the pattern used everywhere else: `span_err`, `span_warning`,
etc.

Author: nnethercote

tests/integration.rs

@@ -69,15 +69,15 @@ fn integration_test() {
     // debug:
     eprintln!("{stderr}");
 
-    // this is an internal test to make sure we would correctly panic on a delay_span_bug
+    // this is an internal test to make sure we would correctly panic on a span_delayed_bug
     if repo_name == "matthiaskrgr/clippy_ci_panic_test" {
         // we need to kind of switch around our logic here:
         // if we find a panic, everything is fine, if we don't panic, SOMETHING is broken about our testing
 
-        // the repo basically just contains a delay_span_bug that forces rustc/clippy to panic:
+        // the repo basically just contains a span_delayed_bug that forces rustc/clippy to panic:
         /*
            #![feature(rustc_attrs)]
-           #[rustc_error(delay_span_bug_from_inside_query)]
+           #[rustc_error(span_delayed_bug_from_inside_query)]
            fn main() {}
         */
 
@@ -86,7 +86,7 @@ fn integration_test() {
             return;
         }
 
-        panic!("panic caused by delay_span_bug was NOT detected! Something is broken!");
+        panic!("panic caused by span_delayed_bug was NOT detected! Something is broken!");
     }
 
     if let Some(backtrace_start) = stderr.find("error: internal compiler error") {