doc: Clarify behavior of --exclude #1399

Job	Run time
Ensure 'cargo clippy' has no warnings	50s
Ensure 'cargo fmt' has been run	11s
Extract crate metadata	3s
Minimum supported rust version	1m 27s
aarch64-unknown-linux-gnu (ubuntu-22.04)	4m 20s
aarch64-unknown-linux-musl (ubuntu-22.04)	5m 30s
arm-unknown-linux-gnueabihf (ubuntu-22.04)	5m 54s
arm-unknown-linux-musleabihf (ubuntu-22.04)	3m 34s
i686-pc-windows-msvc (windows-2022)	3m 59s
i686-unknown-linux-gnu (ubuntu-22.04)	4m 7s
i686-unknown-linux-musl (ubuntu-22.04)	4m 8s
x86_64-apple-darwin (macos-13)	3m 54s
aarch64-apple-darwin (macos-14)	2m 3s
x86_64-pc-windows-gnu (windows-2022)	4m 11s
x86_64-pc-windows-msvc (windows-2022)	3m 51s
x86_64-unknown-linux-gnu (ubuntu-22.04)	4m 1s
x86_64-unknown-linux-musl (ubuntu-22.04)	4m 45s
Publish to Winget	0s
	56m 48s

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