tweaks to changes from #5227

cookbook/form/create_form_type_extension.rst

@@ -19,7 +19,7 @@ Form type extensions have 2 main use-cases:
 #. You want to add a **generic feature to several types** (such as
    adding a "help" text to every "input text"-like type).
 
-It might be possible to achieve your goal with custom form rendering, or custom
+It might be possible to achieve your goal with custom form rendering or custom
 form field types. But using form type extensions can be cleaner (by limiting the
 amount of business logic in templates) and more flexible (you can add several
 type extensions to a single form type).
@@ -331,6 +331,6 @@ these form types.
 
 In the same way, since **most** form types natively available in Symfony inherit
 from the ``form`` form type, a form type extension applying to ``form`` would
-apply to all of these.  A notable exception are the ``button`` form types. Plus,
-keep in mind that a custom form type which inherit neither ``form`` nor
-``button`` could always be created.
+apply to all of these.  A notable exception are the ``button`` form types. Also
+keep in mind that a custom form type which extends neither the ``form`` nor
+the ``button`` type could always be created.