Improving strftime documentation.

Re-ordering the table so similar directives are grouped together, adding
examples, and removing some redundancy in the description of the ``%f``
formatter.
Adding localized examples to strftime documentation.
Correct misleading strftime documentation.

strftime using locale-aware formatting directives will often, but not awlays,
produce UTF-8-encoded Unicode.
Remove Japanese datetime examples
Clarify that strftime's encoding is based on locale
Clean merge
Issue #18226: Add docstrings and unittests for idlelib/FormatParagraph.py.
Move comment code to a separate function so it can be separately tested.
Original patches by Todd Rovito and Phil Webster.
Issue #18429: Add user-oriented News entry about Format / Format Paragraph
now working with comment block selections. Patch was part of 18226 patch.
Issue #18676: Change 'positive' to 'non-negative' in queue.py put and get
docstrings and ValueError messages. Patch by Zhongyue Luo
#18663: document that assertAlmostEqual also works when the values are equal and add tests.
Issue #17701: Improving strftime documentation
Documenting that json.load may raise a ValueError.

Issue #18680: JSONDecoder should document that it raises a ValueError
  for malformed data
Increasing test coverage of ftplib. Patch by Muhammad Jehanzeb
Issue 18724: Fix typo noticed by Susan Tan.
#18687: remove obsolete comment.  Patch by Févry Thibault.
Add NEWS entry for 0f17aed78168 (issue #16248)
Issue #18425: Add docstrings to IdleHistory.py.  Remove redundant 'history_'
prefix from two attributes and two methods of History class.
Issue 18719: Remove a false optimization

Remove an unused early-out test from the critical path for
dict and set lookups.

When the strings already have matching lengths and hashes,
there is no additional information gained by checking the first
characters (the probability of a mismatch is already known to
be less than 1 in 2**64).
Issue #18718: datetime documentation contradictory on leap second support
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.