tiny update to a title

Author: rwaskiewicz

BREAKING_CHANGES.md

@@ -46,7 +46,7 @@ export const config: Config = {
   // ...
 };
 ```
-##### `dist-custom-elements` Types
+##### `dist-custom-elements` Type Declarations
 Type declaration files (`.d.ts` files) are now generated by default for the `dist-custom-elements` output target.
 If your project is using `dist-custom-elements` and you wish to not generate type declarations, the old behavior can be achieved by setting `generateTypeDeclarations` to `false` in your project's `stencil.config.ts`:
 ```ts