Improve fish completion script generation #40

Job	Run time
CMake Build	45s
Validate Format Config	10s
Test / Linux (5.8 - jammy)	56s
Test / Linux (5.9 - jammy)	1m 5s
Test / Windows (6.0 - windows-2022)	16m 18s
Test / Linux (5.10 - jammy)	1m 0s
Test / Windows (nightly - windows-2019)	11m 9s
Test / Linux (6.0 - jammy)	1m 11s
Test / Windows (nightly-6.1 - windows-2019)	10m 29s
Test / Linux (nightly-main - jammy)	1m 31s
Test / Linux (nightly-6.1 - jammy)	1m 30s
Soundness / Broken symlinks check	3s
Soundness / API breakage check	1m 3s
Soundness / Documentation check	56s
Soundness / Format check	34s
Soundness / License headers check	0s
Soundness / Python lint check	5s
Soundness / Shell check	0s
Soundness / Unacceptable language check	3s
Soundness / YAML lint check	4s
	48m 52s

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