Add example for temp scope of while let

Author: traviscross

src/destructors.md

@@ -222,6 +222,7 @@ r[destructors.scope.temporary.edition2024]
 Some examples:
 
 ```rust
+# #![allow(irrefutable_let_patterns)]
 # struct PrintOnDrop(&'static str);
 # impl Drop for PrintOnDrop {
 #     fn drop(&mut self) {
@@ -248,6 +249,13 @@ else {
     // `if let else` dropped here
 };
 
+while let x = PrintOnDrop("while let scrutinee").0 {
+    PrintOnDrop("while let loop body").0;
+    break;
+    // `while let loop body` dropped here.
+    // `while let scrutinee` dropped here.
+}
+
 // Dropped before the first ||
 (PrintOnDrop("first operand").0 == ""
 // Dropped before the )