Typo fix - implemention should be implementation (pythonGH-16806)

(cherry picked from commit 2798b60)

Co-authored-by: Hansraj Das <raj.das.136@gmail.com>

Author: miss-islington

Python/hamt.c

@@ -6,7 +6,7 @@
 #include "structmember.h"
 
 /*
-This file provides an implemention of an immutable mapping using the
+This file provides an implementation of an immutable mapping using the
 Hash Array Mapped Trie (or HAMT) datastructure.
 
 This design allows to have: