TextEditor: edit MIME type description for primitive types

To make it more consistent with the other descriptions.

Change-Id: Ia7b5f046976e5ae18f68e1afba7b971b89898e39
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
UI text: replace "e-mail" with "email"

For consistency.

Change-Id: I0b8244a7d6b86c3fc0cccf24b220e3264f0ee116
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>