#19395: Raise exception when pickling a (BZ2|LZMA)(Compressor|Decompressor).

The underlying C libraries provide no mechanism for serializing compressor and
decompressor objects, so actually pickling these classes is impractical.
Previously, these objects would be pickled without error, but attempting to use
a deserialized instance would segfault the interpreter.
Issue #19425 -- a pickling error should not cause pool to hang.
Fix typo: js_JP is not a valid locale.
Fix wrong signature for two-argument newwin().  Found by Jacqueline Leykam on docs@.
Closes #19416: fix references in the nntplib docs.
Clarify sentence.