[TwigBridge] Fix switch-custom changelog entry

As it doesn't really mention `switch-custom` is a css class.

Author: ogizanagi

CHANGELOG.md

@@ -10,7 +10,7 @@ CHANGELOG
  * the `LintCommand` lints all the templates stored in all configured Twig paths if none argument is provided
  * deprecated accepting STDIN implicitly when using the `lint:twig` command, use `lint:twig -` (append a dash) instead to make it explicit.
  * added `--show-deprecations` option to the `lint:twig` command
- * added support for Bootstrap4 switches, use `switch-custom` as `label_attr` in a `CheckboxType`
+ * added support for Bootstrap4 switches: add the `switch-custom` class to the label attributes of a `CheckboxType`
  * Marked the `TwigDataCollector` class as `@final`.
 
 4.3.0