Reword the title of this section

This is intended since there are multiple ways to suppress a destructor.

Author: ehuss

src/destructors.md

@@ -420,9 +420,9 @@ let x = (&temp()).use_temp();  // ERROR
 
 ## Not running destructors
 
-### `forget`
+### Manually preventing destructors
 
-r[destructors.forget]
+r[destructors.manually-preventing]
 
 [`std::mem::forget`] can be used to prevent the destructor of a variable from being run,
 and [`std::mem::ManuallyDrop`] provides a wrapper to prevent a