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.

compiler/rustc_query_system/src/query/plumbing.rs

@@ -138,7 +138,7 @@ where
                 && let Some(span) = root.query.span
             {
                 error.stash(span, StashKey::Cycle);
-                qcx.dep_context().sess().delay_span_bug(span, "delayed cycle error")
+                qcx.dep_context().sess().span_delayed_bug(span, "delayed cycle error")
             } else {
                 error.emit()
             };
@@ -421,7 +421,7 @@ where
                 // We have an inconsistency. This can happen if one of the two
                 // results is tainted by errors. In this case, delay a bug to
                 // ensure compilation is doomed.
-                qcx.dep_context().sess().delay_span_bug(
+                qcx.dep_context().sess().span_delayed_bug(
                     DUMMY_SP,
                     format!(
                         "Computed query value for {:?}({:?}) is inconsistent with fed value,\n\