Python: Fix typo

Author: tausbn

python/ql/test/experimental/dataflow/tainttracking/unwanted-global-flow/test.py

@@ -40,7 +40,7 @@ def use_of_initially_tainted2():
 ensure_not_tainted(initially_tainted2)
 
 
-# Flow via global assigment
+# Flow via global assignment
 
 def write_tainted():
     global g