Update clippy_lints/src/let_underscore.rs

Co-authored-by: Philipp Krones <hello@philkrones.com>

Author: smoelius

clippy_lints/src/let_underscore.rs

@@ -79,12 +79,20 @@ declare_clippy_lint! {
     /// impl Drop for Droppable {
     ///     fn drop(&mut self) {}
     /// }
-    /// let _ = Droppable;
+    /// {
+    ///     let _ = Droppable;
+    ///     //               ^ dropped here
+    ///     /* more code */
+    /// }
     /// ```
     ///
     /// Good:
     /// ```rust,ignore
-    /// let _droppable = Droppable;
+    /// {
+    ///     let _droppable = Droppable;
+    ///     /* more code */
+    ///     // dropped at end of scope
+    /// }
     /// ```
     pub LET_UNDERSCORE_DROP,
     correctness,