bpo-22377: Fixes documentation for %Z in datetime (GH-16507)



This fixes the issue discussed in https://bugs.python.org/issue22377
and fixes it according to the comments made by Paul Ganssle @pganssle

* It clarifies which values are acceptable in the table
* It extends the note with a clearer information on the valid values


https://bugs.python.org/issue22377
2 files changed