Add documentation about quiet configuration

Author: l-vo

components/phpunit_bridge.rst

@@ -296,6 +296,8 @@ By default, the bridge will display a detailed output with the number of
 deprecations and where they arise. If this is too much for you, you can use
 ``SYMFONY_DEPRECATIONS_HELPER=verbose=0`` to turn the verbose output off.
 
+It's also possible to change verbosity per deprecation type, for instance ``quiet[]=indirect&quiet[]=other`` will hide details for deprecations of types "indirect" and "other".
+
 Disabling the Deprecation Helper
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~