Clarifies X::Control, refs #2871

doc/Type/X/Control.pod6

@@ -10,12 +10,12 @@ This role turns an exception into a
 L<control exception|/language/exceptions#Control_exceptions>, such as
 C<CX::Next> or C<CX::Take>. It has got no code other than the definition.
 
-Since Rakudo 2019.03, C<throw>ing an C<X::Control> object raises a control
-exception which is caught by the L<CONTROL phaser|/language/phasers#CONTROL>
-instead of L<CATCH|/language/phasers#CATCH>. This allows to define custom
-control exceptions.
+Since Rakudo 2019.03, C<throw>ing an object that mixes in this role
+C<X::Control> can raise a control exception which is caught by the L<CONTROL
+phaser|/language/phasers#CONTROL> instead of L<CATCH|/language/phasers#CATCH>.
+This allows to define custom control exceptions.
 
-For example
+For example, the custom C<CX::Oops> control exception we define below:
 
 =begin code
 class CX::Oops does X::Control {