Updated classes/matrix32

The 3 members of a matrix 32 are Vector2, not float.  Updated
documentation to reflect this.

doc/base/classes.xml

@@ -16517,11 +16517,11 @@
 		</method>
 	</methods>
 	<members>
-		<member name="x" type="float">
+		<member name="x" type="Vector2">
 		</member>
-		<member name="y" type="float">
+		<member name="y" type="Vector2">
 		</member>
-		<member name="o" type="float">
+		<member name="o" type="Vector2">
 		</member>
 	</members>
 	<constants>