Improve docstring

Author: nicoddemus

pytestqt/qt_compat.py

@@ -20,8 +20,8 @@ class _QtApi:
     """
     Interface to the underlying Qt API currently configured for pytest-qt.
 
-    This object lazily loads all class references and other objects upon the ``set_qt_api`` method,
-    providing a uniform way to access the Qt classes.
+    This object lazily loads all class references and other objects when the ``set_qt_api`` method
+    gets called, providing a uniform way to access the Qt classes.
     """
 
     def _get_qt_api_from_env(self):