Fix typos

overridding should be overriding.

Author: Goles

docs/OptimizationTips.rst

@@ -137,12 +137,12 @@ Advice: Use 'private' when declaration does not need to be accessed outside of f
 
 Applying the ``private`` keyword to a declaration restricts the visibility of
 the declaration to the file in which it is declared. This allows the compiler to
-be able to ascertain all other potentially overridding declarations. Thus the
+be able to ascertain all other potentially overriding declarations. Thus the
 absence of any such declarations enables the compiler to infer the ``final``
 keyword automatically and remove indirect calls for methods and field accesses
 accordingly. For instance in the following, ``e.doSomething()`` and
 ``f.myPrivateVar``, will be able to be accessed directly assuming ``E``, ``F``
-do not have any overridding declarations in the same file:
+do not have any overriding declarations in the same file:
 
 ::