Doc: Fix typos

Change-Id: I720813b126f02d4813c88811316a0fa99961c6d8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/gui/opengl/qopenglpaintdevice.cpp

@@ -81,7 +81,7 @@ QT_BEGIN_NAMESPACE
     multisampling. Most hardware require significantly more memory to
     do multisampling and the resulting quality is not on par with the
     quality of the software paint engine. The OpenGL paint engine's
-    strenght lies in its performance, not its visual rendering
+    strength lies in its performance, not its visual rendering
     quality.
 
     \section1 State Changes

src/opengl/doc/src/qtopengl-index.qdoc

@@ -68,5 +68,5 @@
     non-OpenGL-specific GUI functionality.
 
     The \l{Qt OpenGL C++ Classes} page gives an overview over the available classes
-    int this module.
+    in this module.
 */

src/xml/doc/src/qtxml-index.qdoc

@@ -44,5 +44,5 @@
     \snippet code/doc_src_qtxml.pro 1
 
     The \l{Qt XML C++ Classes} page gives an overview over the available classes
-    int this module.
+    in this module.
 */