test: add test case for inlay hint support for expr with label

Author: Young-Flash

src/tools/rust-analyzer/crates/ide/src/inlay_hints/closing_brace.rs

@@ -240,6 +240,19 @@ fn test() {
       //^ 'do_a
     }
   //^ 'end
+
+    'a: loop {
+        'b: for i in 0..5 {
+            'c: while true {
+
+
+            }
+          //^ 'c
+        }
+      //^ 'b
+    }
+  //^ 'a
+
   }
 //^ fn test
 "#,