wave.

- Merge from 3.3
- Added to What's New since these are more important in 3.x,
  as the bytes<->bytes and str<->str codecs don't fit the
  text model convenience methods in 3.x the way they did the
  basestring<->basestring methods in the 2.x text model
- Included under Library in Misc/NEWS for the same reason

wave.

is pre-initialized to that value.  Test show a 5% speedup as a bonus.

pattern at both ends of the string to match.

Patch by Matthew Barnett.
Closes #16203.

CID 486239: Uninitialized pointer read (UNINIT)

Issue #19218: set __name__ of _collections_abc to collections.abc in order to fix tests and keep beautiful qualified names.

This does not fix #19227, but should stop the Gentoo buildbot from hanging.