Use pyrepl+fanycompleter as the default readline for pdb

Feature or enhancement

Proposal:

Once https://github.com/python/cpython/pull/130473 is merged, we can think of using it also for pdb.
This would enable colored completion from the pdb prompt, like this (for context, pdb++ has been doing this for years)

This raises some minor questions such as whether the (pdb) prompt should be white or magenta.

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-141619

先阅读 PR 130473 中引用的 pyrepl 和 fanycompleter 工作，然后检查 pdb 如何选择其 readline 实现以及如何处理 (pdb) 提示符。当 pdb 默认使用 pyrepl+fanycompleter 并提供彩色补全时，此更改即完成；提示符颜色的选择仍需解决。PR 141619 表明这项工作已经在进行中。