Group options and arguments by topic

[nitpick] too many commands

1) Group options by topic when running `just --help` from the command line
2) Same thing with commands

a) recipe listing / selection
--choose
--list
--groups
--summary

b) justfile formatting / checking
--fmt
--check

c) justfile management
--init
--dump
--edit

d) variables
--variables
--evaluate

e) help
--help
--changelog
--man

f) others
--version
--completions

Start at the implementation of the `just --help` command and inspect how its options and commands are currently listed. Group them under the topics shown in the issue, then run `just --help` to verify that the output matches the proposed organization.

Written by the indexing model from the issue text.