Fixed minor syntax issues and typos

Author: javiereguiluz

email/spool.rst

@@ -144,18 +144,18 @@ at a regular interval.
 
 .. caution::
 
-    When you create a message with swiftmailer, it generate a Swift_Message
-    class. If the swiftmailer service is lazy loaded, it generate instead a
-    proxy class named  Swift_Message_<someRandomCharacters>.
+    When you create a message with SwiftMailer, it generates a ``Swift_Message``
+    class. If the ``swiftmailer`` service is lazy loaded, it generates instead a
+    proxy class named ``Swift_Message_<someRandomCharacters>``.
 
-    If you use the memory spool, this change is transparent and has no impart.
-    But when you use the filesystem spool, the message class is serialized on
+    If you use the memory spool, this change is transparent and has no impact.
+    But when using the filesystem spool, the message class is serialized in
     a file with the randomized class name. The problem is that this random 
-    class name change on every cache clear. So if you send a mail, then you
+    class name changes on every cache clear. So if you send a mail and then you
     clear the cache, the message will not be unserializable.
 
-    On the next ``swiftmailer:spool:send`` an error will raise because the
-    class ``Swift_Message_<someRandomCharacters>`` doesn't exist (anymore).
+    On the next execution of ``swiftmailer:spool:send`` an error will raise because
+    the class ``Swift_Message_<someRandomCharacters>`` doesn't exist (anymore).
 
     The solutions are either to use the memory spool or to load the 
-    swiftmailer service without ``lazy`` option (see :doc:`/service_container/lazy_services`).
+    ``swiftmailer`` service without ``lazy`` option (see :doc:`/service_container/lazy_services`).