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/Python/bootstrap_hash.c b/Python/bootstrap_hash.c
index 43f5264..aa3a3df 100644
--- a/Python/bootstrap_hash.c
+++ b/Python/bootstrap_hash.c
@@ -163,7 +163,7 @@
             }
 
             /* getrandom(GRND_NONBLOCK) fails with EAGAIN if the system urandom
-               is not initialiazed yet. For _PyRandom_Init(), we ignore the
+               is not initialized yet. For _PyRandom_Init(), we ignore the
                error and fall back on reading /dev/urandom which never blocks,
                even if the system urandom is not initialized yet:
                see the PEP 524. */