Fixed typo in docs/ref/contrib/gis/geos.txt.

docs/ref/contrib/gis/geos.txt

@@ -226,7 +226,7 @@ Returns a boolean indicating whether the geometry is a ``LinearRing``.
 Returns a boolean indicating whether the geometry is 'simple'. A geometry
 is simple if and only if it does not intersect itself (except at boundary
 points).  For example, a :class:`LineString` object is not simple if it
-intersects itself. Thus, :class:`LinearRing` and :class`Polygon` objects
+intersects itself. Thus, :class:`LinearRing` and :class:`Polygon` objects
 are always simple because they do cannot intersect themselves, by
 definition.