Fix typos in comments, docs and test names (#15018)

* Fix typos in comments, docs and test names

* Update test_pyparse.py

account for change in string length

* Apply suggestion: splitable -> splittable

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Apply suggestion: splitable -> splittable

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Apply suggestion: Dealloccte -> Deallocate

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Update posixmodule checksum.

* Reverse idlelib changes.
diff --git a/Lib/test/test_pprint.py b/Lib/test/test_pprint.py
index b3b8715..cf3e4f0 100644
--- a/Lib/test/test_pprint.py
+++ b/Lib/test/test_pprint.py
@@ -481,7 +481,7 @@
         # Consequently, this test is fragile and
         # implementation-dependent.  Small changes to Python's sort
         # algorithm cause the test to fail when it should pass.
-        # XXX Or changes to the dictionary implmentation...
+        # XXX Or changes to the dictionary implementation...
 
         cube_repr_tgt = """\
 {frozenset(): frozenset({frozenset({2}), frozenset({0}), frozenset({1})}),