Optimized copying and deepcopying bytearrays, NotImplemented, slices,
short lists, tuples, dicts, sets.

Output of func(*args) stored in the next line:

    item_help = join([func(*args) for func, args in self.items])

_Section.items only used by HelpFormatter._add_item() and it looks
like it doesn't have any side effects.

Patch by Yogesh Chaudhari.

Patch by Liang-Bo Wang.

Patch by Liang-Bo Wang.

Patch by Liang-Bo Wang.

other write methods.

Patch by Jakub Stasiak.

Issue #25888

Patch by Sebastien Bourdeauducq (issue #26338)

Patch by Frederick Wagner (issue #26347)

Patch by Chris Angelico (issue #26221)

Patch by Vladimir Rutsky.

In practice, bytecode instruction arguments are unsigned. Update the assertion
to make it more explicit that argument must be greater or equal than 0.

Rewrite also the comment.