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/

crates/printer/Cargo.toml

@@ -16,7 +16,7 @@ edition = "2021"
 
 [features]
 default = ["serde"]
-serde = ["dep:base64", "dep:serde", "dep:serde_derive", "dep:serde_json"]
+serde = ["dep:base64", "dep:serde", "dep:serde_json"]
 
 [dependencies]
 base64 = { version = "0.21.4", optional = true }
@@ -26,7 +26,6 @@ grep-searcher = { version = "0.1.11", path = "../searcher" }
 log = "0.4.5"
 termcolor = "1.3.0"
 serde = { version = "1.0.193", optional = true }
-serde_derive = { version = "1.0.193", optional = true }
 serde_json = { version = "1.0.107", optional = true }
 
 [dev-dependencies]