Fix `make uninstall` to remove fish completion #13273

Job	Run time
check_format	1m 41s
x86_64-gnu-test (1.7.3)	34m 33s
x86_64-gnu-test (1.8.2)	36m 26s
x86_64-gnu-test-preview_mt	5m 47s
x86_64-gnu-test (1.9.2)	35m 5s
x86_64-musl-test	37m 11s
x86_64-gnu-test (1.10.1)	34m 35s
x86_64-gnu-test (1.11.2)	33m 54s
x86_64-gnu-test (1.12.2)	33m 22s
x86_64-gnu-test (1.13.3)	32m 54s
x86_64-gnu-test (1.14.1)	33m 46s
x86_64-gnu-test (1.15.0)	33m 48s
x86_64-gnu-test (1.0.0, FLAGS=-Dwithout_ffi USE_PCRE1=true)	32m 43s
x86_64-gnu-test (1.1.1, FLAGS=-Dwithout_ffi USE_PCRE1=true)	34m 42s
x86_64-gnu-test (1.2.2, USE_PCRE1=true)	35m 0s
x86_64-gnu-test (1.3.2, USE_PCRE1=true)	34m 34s
x86_64-gnu-test (1.4.1, USE_PCRE1=true)	34m 23s
x86_64-gnu-test (1.5.1, USE_PCRE1=true)	32m 11s
x86_64-gnu-test (1.6.2, USE_PCRE1=true)	33m 46s
	9h 50m 21s

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