Improvements and fixes to zsh completion #3197

Job	Run time
Ensure 'cargo fmt' has been run	5s
Documentation	44s
cargo audit	8s
Extract crate metadata	4s
License checks	55s
Run tests with updated syntaxes and themes	5m 43s
Run tests with system wide configuration	2m 15s
Minimum supported rust version	1m 18s
aarch64-unknown-linux-gnu (ubuntu-20.04)	4m 6s
arm-unknown-linux-gnueabihf (ubuntu-20.04)	3m 34s
arm-unknown-linux-musleabihf (ubuntu-20.04)	3m 53s
i686-pc-windows-msvc (windows-2019)	7m 45s
i686-unknown-linux-gnu (ubuntu-20.04)	3m 26s
i686-unknown-linux-musl (ubuntu-20.04)	4m 5s
x86_64-apple-darwin (macos-12)	8m 27s
x86_64-pc-windows-gnu (windows-2019)	8m 3s
x86_64-pc-windows-msvc (windows-2019)	6m 18s
x86_64-unknown-linux-gnu (ubuntu-20.04)	3m 28s
x86_64-unknown-linux-musl (ubuntu-20.04)	3m 42s
all-jobs	1s
Publish to Winget	0s
	1h 8m 0s

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