Add the interpreters Module, Implementing PEP 734

Feature or enhancement

Proposal:

(This is effectively the successor issue to gh-76785.)

Assuming PEP 734 is accepted (hopefully for 3.14), this issue covers the implementation.

Note that the base implementation already exists as Lib/test/support/interpreters. Thus "implementing" the PEP will amount to moving the files to Lib/interpreters and updating associated references.

TODO:

• move files from Lib/test/support/interpreters to Lib/interpreters
• add Docs/library/interpreters.rst, etc.
• add a multiple-interpreters howto doc (related: Add A Howto Page About Concurrency in Python #123152)
• update InterpreterPoolExecutor to use interpreters.Interpreter

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-134939: Add the interpreters Module #133958
• [3.14] gh-134939: Add the concurrent.interpreters Module #135414
• gh-134939: Fill Out the concurrent.interpreters Docs #135902
• [3.14] gh-134939: Fill Out the concurrent.interpreters Docs (gh-135902) #136141
• gh-134939: Add a Multiple Interpreters Howto Doc #136143
• gh-134939: Correct concurrent.interpreters source code link #136564
• [3.14] gh-134939: Correct concurrent.interpreters source code link (GH-136564) #136605