docs(guide/component): clarify when to use directives instead of components

Clarify that components cannot be used to perform actions in compile
and prelink functions.

Closes angular#15042
PR (angular#15100)

Author: austinoneil

docs/content/guide/component.ngdoc

@@ -19,8 +19,7 @@ Advantages of Components:
 
 When not to use Components:
 
-- for directives that rely on DOM manipulation, adding event listeners etc, because the compile
-and link functions are unavailable
+- for directives that need to perform actions in compile and pre-link functions, because they aren't available
 - when you need advanced directive definition options like priority, terminal, multi-element
 - when you want a directive that is triggered by an attribute or CSS class, rather than an element