Remove blurb split; after 3.2 NEWS is generated from next/*, not vice versa

[arhadthedev]

The blurb split command fixes known historical issues of Misc/NEWS and splits it into Misc/NEWS.d/*.rst.

However, it lost any use in Python 3.2 when it was replaced with direct committing of Misc/NEWS.d/*.*.*.rst.

So this PR:

• removes this command
• cleans up leftover functions&imports
• replaces verbal mentions of Misc/NEWS with mentions of Misc/NEWS.d and Misc/NEWS.d/next.

Edit: initially I was way too ambitious and desired to remove blurb merge as well

The blurb tool has two commands that manipulate Misc/NEWS file. However, they lost any use in Python 3.2 when it was replaced with direct committing of Misc/NEWS.d/*.*.*.rst. These commands are:

• blurb merge (glues new Misc/NEWS.d/*.rst into old Misc/NEWS)
• blurb split (fixes known historical issues of Misc/NEWS and splits it back into Misc/NEWS.d/*.rst)
• it was performed last time in python/cpython@260a788 and was never used again

This PR removes these commands, cleans up leftover functions&imports, and replaces verbal mentions of Misc/NEWS with mentions of Misc/NEWS.d or Misc/NEWS.d/next.

[hugovk]

The blurb tool has two commands that manipulate Misc/NEWS file. However, they lost any use in Python 3.2 when it was replaced with direct committing of Misc/NEWS.d/*.*.*.rst.

Does that mean we don't need python/cpython#30419 and #147?

If so, there's a bunch of blurb NEWS stuff that could be removed from https://github.com/python/cpython/blob/main/Doc/Makefile.

[arhadthedev]

@hugovk Thank you for noticing! I looked further and found that blurb merge is used to generate NEWS.txt for Windows distribution. So I reverted this command back.

[arhadthedev]

@larryhastings ping

[arhadthedev]

@larryhastings Can this PR be merged, please?

[arhadthedev]

Someone please?

[arhadthedev]

Erm... ping?

[gpshead]

If for some reason we ever needed this again, that is what we have a version control system for. :)