Switch to generating completions at runtime #2678

Job	Run time
Rustfmt and clippy	58s
Test (x86_64-unknown-linux-gnu, ubuntu-latest, --features=native-tls)	1m 2s
Test (x86_64-unknown-linux-gnu, ubuntu-latest, --no-default-features --features=native-tls,online...	1m 3s
Test (x86_64-apple-darwin, macos-13, --features=native-tls)	3m 2s
Test (aarch64-apple-darwin, macos-14, --features=native-tls)	1m 51s
Test (x86_64-pc-windows-msvc, windows-latest, --features=native-tls)	2m 25s
Test (x86_64-unknown-linux-musl, ubuntu-latest, true)	1m 42s
Test (aarch64-unknown-linux-musl, ubuntu-latest, true, -- --test-threads=4)	2m 26s
Test (arm-unknown-linux-gnueabihf, ubuntu-latest, true, -- --test-threads=4)	2m 23s
	16m 52s

Provide feedback