Increasing test coverage of ftplib. Patch by Muhammad Jehanzeb

Issue #18680: JSONDecoder should document that it raises a ValueError
  for malformed data

Issue #18680: JSONDecoder should document that it raises a ValueError
  for malformed data

Issue #18680: JSONDecoder should document that it raises a ValueError
  for malformed data

Issue #18680: JSONDecoder should document that it raises a ValueError
  for malformed data

Issue #18585: Add :func:`textwrap.shorten` to collapse and truncate a piece of text to a given length.

importlib.import_module() include the name of the module when the
'package' argument is missing but needed.

Patch by Neil Schemenauer, minimally modified.

(re-apply after fix for tkinter-related crash)

(issue #15721)

docstrings and ValueError messages. Patch by Zhongyue Luo

now working with comment block selections. Patch was part of 18226 patch.

Move comment code to a separate function so it can be separately tested.
Original patches by Todd Rovito and Phil Webster.