cargo: enable the watchman feature by default #6769

Job	Run time
Check protos	45s
Check protos	45s
cargo-deny (advisories)	3m 10s
cargo-deny (advisories)	3m 10s
cargo-deny (bans licenses sources)	37s
cargo-deny (bans licenses sources)	37s
build (ubuntu-latest)	2m 53s
build (ubuntu-latest)	8m 47s
build (macos-13)	4m 20s
build (macos-13)	4m 20s
build (windows-latest)	12m 10s
build (windows-latest)	12m 10s
build (ubuntu-latest, --all-features)	6m 35s
build (ubuntu-latest, --all-features)	6m 35s
Clippy check	2m 58s
Clippy check	2m 58s
Check that MkDocs can build the docs	33s
Check that MkDocs can build the docs	33s
Check formatting	19s
Check formatting	19s
	1h 14m 34s

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