Clean up documentation a bit re. named choice
Clean up documentation a bit re. named choice

Zephyr uses several named choices, and I've seen them in other projects
now too, so don't imply that they aren't used. The menuconfig interface
now has better support for them than the C tools too, where adding
symbols by defining a choice in multiple locations is broken.

Also remove a reference to Kconfiglib 1.

ulfalizer/Kconfiglib,ulfalizer/Kconfiglib