Fix typos mostly in comments, docs and test names (GH-15209)

(cherry picked from commit 39d87b54715197ca9dcb6902bb43461c0ed701a2)

Co-authored-by: Min ho Kim <minho42@gmail.com>
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 1042ea7..15bfe26 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -4523,7 +4523,7 @@
     /* Initialize reference count to avoid early crash in ceval or GC */
     Py_REFCNT(op) = 1;
     /* ob_type field is after the memory block: part of "forbidden bytes"
-       when using debug hooks on memory allocatrs! */
+       when using debug hooks on memory allocators! */
     return test_pyobject_is_freed("check_pyobject_forbidden_bytes_is_freed", op);
 }