Update src/drop-flags.md

src/drop-flags.md

@@ -79,5 +79,5 @@ if condition {
 }
 ```
 
-The drop flags are tracked on the stack. In old Rust versions, drop flags were
+The drop flags are tracked on the stack.
-stashed in a hidden field of types that implement Drop.
+In old Rust versions, drop flags were stashed in a hidden field of types that implement `Drop`.