bug #6368 [cookbook] Made list of form types more consistent (AAstakhov)

This PR was merged into the 2.8 branch.

Discussion
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[cookbook] Made list of form types more consistent

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.8+
| Fixed tickets | n/a

Fixed content of inline code block 'email' to 'EmailType' accordingly to other form types in the list.

Commits
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993fc45 Made list of types more consistent

cookbook/form/create_form_type_extension.rst

@@ -329,7 +329,7 @@ Generic Form Type Extensions
 
 You can modify several form types at once by specifying their common parent
 (:doc:`/reference/forms/types`). For example, several form types natively
-available in Symfony inherit from the ``TextType`` form type (such as ``email``,
+available in Symfony inherit from the ``TextType`` form type (such as ``EmailType``,
 ``SearchType``, ``UrlType``, etc.). A form type extension applying to ``TextType``
 (i.e. whose ``getExtendedType`` method returns ``TextType::class``) would apply
 to all of these form types.