docs/*/quickref.rst: Use new semantics of ticks_diff()

docs/reference/speed_python.rst

@@ -132,7 +132,7 @@ The following enables any function or method to be timed by adding an
         def new_func(*args, **kwargs):
             t = time.ticks_us()
             result = f(*args, **kwargs)
-            delta = time.ticks_diff(t, time.ticks_us())
+            delta = time.ticks_diff(time.ticks_us(), t)
             print('Function {} Time = {:6.3f}ms'.format(myname, delta/1000))
             return result
         return new_func