rust/Cargo.toml

rust: use `logging_timer` instead of `micro_timer`

I am the author of `micro_timer`.
I built it at the time because I couldn't find a crate that was simple to use
and flexible to do function timing with. Turns out I just couldn't find it
because crates.io's search isn't all that great, or maybe I didn't look hard
enough.

`logging_timer` is better in every way:
    - supports changing the logging level
    - supports start and end logging
    - supports intermediary messages
    - supports inline macros
    - supports formatting the output
    - better IDE/tree-sitter integration thanks to a more robust proc macro

I also changed all uses to one-liners, so it's easier to copy-paste.

[workspace]
members = ["hg-core", "hg-cpython", "rhg"]
exclude = ["chg", "hgcli"]