Since `uv`'s cpython distributions are built this way `pdbp`'s tab
completion was breaking (as was vi-mode). This adds a new
`.devx._enable_readline_feats()` import hook which checks for the
appropriate library and applies settings accordingly.
Namely since i use `xonsh` for a main shell, this includes adding it as
well as related tooling. Obvi bump the `uv.lock`.
Some other stuff retained from `poetry` days,
- add usage-comments around various (optional) deps.
- add toml section separator lines.
- go with 2-space indent.
- add comment on `trio>0.27` needed for py3.13+