Alphabetize the `[perfectionist::*]` rule tables in `dylint.toml`

[KSXGitHub]

After moving clap_help_markdown to the top (PR #437, #discussion_r3488718785), the per-rule tables in dylint.toml are still not fully alphabetical:

["perfectionist::clap_help_markdown"]
["perfectionist::unordered_derives"]          # <- out of order (u should be last)
["perfectionist::import_granularity_mismatch"]
["perfectionist::import_grouping_mismatch"]
["perfectionist::impure_macro_arguments"]
["perfectionist::single_letter_closure_param"]

Fully alphabetical would be:

["perfectionist::clap_help_markdown"]
["perfectionist::import_granularity_mismatch"]
["perfectionist::import_grouping_mismatch"]
["perfectionist::impure_macro_arguments"]
["perfectionist::single_letter_closure_param"]
["perfectionist::unordered_derives"]

i.e. unordered_derives should move to the bottom. That reorders tables not otherwise related to PR #437, so it's split out here rather than folded into that PR.