improve diagnostics for const eval query overflow

compiler/rustc_query_system/src/error.rs

@@ -84,14 +84,14 @@ pub struct QueryOverflow {
     #[primary_span]
     pub span: Option<Span>,
     #[subdiagnostic]
-    pub layout_of_depth: Option<LayoutOfDepth>,
+    pub note: Option<QueryOverflowNote>,
     pub suggested_limit: Limit,
     pub crate_name: Symbol,
 }
 
 #[derive(Subdiagnostic)]
-#[note(query_system_layout_of_depth)]
-pub struct LayoutOfDepth {
+#[note(query_system_overflow_note)]
+pub struct QueryOverflowNote {
     pub desc: String,
     pub depth: usize,
 }