Fix typo in tutorial

Doc/tutorial/controlflow.rst

@@ -167,7 +167,7 @@ The :keyword:`continue` statement, also borrowed from C, continues with the next
 iteration of the loop::
 
     >>> for num in range(2, 10):
-    ...     if x % 2 == 0:
+    ...     if num % 2 == 0:
     ...         print("Found an even number", num)
     ...         continue
     ...     print("Found a number", num)