Optionally alphabetically sort recipes in `--dump` and `--fmt`

In order to maintain clean justfile, it would be useful to be able to sort the file by recipe name. Thx!

In the mean time, I wrote a python script that sorts justfiles: https://gist.github.com/nyurik/8a6db6bfcd0eb7de52287071e63c8ac5

Start by tracing the command paths for `--dump` and `--fmt` in the just CLI, then identify where recipe names are collected and rendered. Implement optional alphabetical ordering while preserving the existing output behavior when sorting is not requested, and verify both modes with the relevant test or command output.

Written by the indexing model from the issue text.