perf: add inline to Drop impls

Author: ryota2357

src/lib.rs

@@ -916,6 +916,7 @@ impl Clone for LeanString {
 ///
 /// This ensures no memory leaks occur and all resources are properly cleaned up.
 impl Drop for LeanString {
+    #[inline]
     fn drop(&mut self) {
         self.0.replace_inner(Repr::new());
     }

src/repr.rs

@@ -412,6 +412,7 @@ impl Repr {
         }
 
         impl Drop for SetLenOnDrop<'_> {
+            #[inline]
             fn drop(&mut self) {
                 // SAFETY:
                 // - `dst_idx <= src_idx`, and `src_idx <= len`, so `dst_idx <= len`.