fix some minor typos

cookbook/email/gmail.rst

@@ -129,7 +129,7 @@ that you `allow less secure apps to access your Gmail account`_.
 
 .. seealso::
 
-    see the :doc:`Swiftmailer configuration reference </reference/configuration/swiftmailer>`
+    See the :doc:`Swiftmailer configuration reference </reference/configuration/swiftmailer>`
     for more details.
 
 .. _`generate an App password`: https://support.google.com/accounts/answer/185833

reference/forms/types/button.rst

@@ -5,7 +5,7 @@ button Field Type
 =================
 
 .. versionadded:: 2.3
-    The ``button`` type was introduced in Symfony 2.3
+    The ``button`` type was introduced in Symfony 2.3.
 
 A simple, non-responsive button.
 

reference/forms/types/reset.rst

@@ -5,7 +5,7 @@ reset Field Type
 ================
 
 .. versionadded:: 2.3
-    The ``reset`` type was introduced in Symfony 2.3
+    The ``reset`` type was introduced in Symfony 2.3.
 
 A button that resets all fields to their original values.
 

reference/forms/types/submit.rst

@@ -5,7 +5,7 @@ submit Field Type
 =================
 
 .. versionadded:: 2.3
-    The ``submit`` type was introduced in Symfony 2.3
+    The ``submit`` type was introduced in Symfony 2.3.
 
 A submit button.