printer: drop dependency on serde_derive

As suggested by @epage[1].

Ad hoc timings on my i7-12900K:

    before cargo build: 4.91s
    before cargo build release: 8.05s
    after cargo build: 4.69s
    after cargo build release: 7.83s

... pretty underwhelming if you ask me. Ah well. And on my M2 mac mini:

    before cargo build: 6.18s
    before cargo build release: 14.50s
    after cargo build: 5.52s
    after cargo build release: 13.44s

Still kind of underwhelming, but definitely better. It shaves a full
second off of compile times in release mode. I went back to my
i7-12900K, but passed `-j1` to `cargo build` to force single threaded
mode:

    before cargo build: 19.44s
    before cargo build release: 50.64s
    after cargo build: 16.76s
    after cargo build release: 48.00s

Which seems pretty consistent with the modest improvements above.

Looking at `cargo build --timings`, the beefiest chunk of time is spent
in compiling `regex-automata`, by far. This is fine because it's core
functionality. I wish a fast general purpose regex engine with its
internals exposed as a separately versioned library didn't require so
much code... Blech.

[1]: https://old.reddit.com/r/rust/comments/17rd8ww/faster_compilation_with_the_parallel_frontend_in/k8igjlg/

Cargo.lock

@@ -192,7 +192,6 @@ dependencies = [
  "grep-searcher",
  "log",
  "serde",
- "serde_derive",
  "serde_json",
  "termcolor",
 ]