[1.7.x] Various documentation typo/spelling fixes

Errors detected by Topy (https://github.com/intgr/topy), all changes
verified by hand.

Backport of 11d453bcad from master

docs/ref/contrib/admin/actions.txt

@@ -145,7 +145,7 @@ Handling errors in actions
 
 If there are foreseeable error conditions that may occur while running your
 action, you should gracefully inform the user of the problem. This means
-handling exceptions and and using
+handling exceptions and using
 :meth:`django.contrib.admin.ModelAdmin.message_user` to display a user friendly
 description of the problem in the response.
 

docs/ref/contrib/formtools/form-wizard.txt

@@ -106,7 +106,7 @@ respectively).
     in the :doc:`sessions documentation </topics/http/sessions>` on
     how to enable sessions.
 
-We will use the :class:`SessionWizardView` in all examples but is is completely
+We will use the :class:`SessionWizardView` in all examples but is completely
 fine to use the :class:`CookieWizardView` instead. As with your
 :class:`~django.forms.Form` classes, this :class:`WizardView` class can live
 anywhere in your codebase, but convention is to put it in :file:`views.py`.

docs/ref/contrib/gis/gdal.txt

@@ -739,7 +739,7 @@ systems and coordinate transformation::
    .. attribute:: z
 
    Returns the Z coordinate of this point, or ``None`` if the
-   the point does not have a Z coordinate::
+   point does not have a Z coordinate::
 
        >>> OGRGeometry('POINT (1 2 3)').z
        3.0

docs/ref/contrib/gis/geos.txt

@@ -880,7 +880,7 @@ Returns WKB of the geometry in hexadecimal.  Example::
 
 .. attribute:: WKBWriter.byteorder
 
-This property may be be set to change the byte-order of the geometry
+This property may be set to change the byte-order of the geometry
 representation.
 
 =============== =================================================