Add more warnings to crate root #2130

Job	Run time
Check formatting	16s
Check formatting	16s
Check MSRV	1m 57s
Check MSRV	1m 57s
Lint macOS 64bit	4m 51s
Lint macOS 64bit	4m 51s
Lint iOS 32bit	1m 50s
Lint iOS 32bit	1m 50s
Lint GNUStep + exceptions	2m 56s
Lint GNUStep + exceptions	2m 56s
Lint header-translator	1m 14s
Lint header-translator	1m 14s
Lint test-assembly	42s
Lint test-assembly	42s
Test macOS 12	8m 51s
Test macOS 12	8m 51s
Assembly tests	1m 11s
Assembly tests	1m 11s
Test Compiler-RT	1m 3s
Test Compiler-RT	1m 3s
Verify header translator output	59s
Verify header translator output	59s
Check icrate features	0s
Check icrate features	0s
Test GNUStep with libobjc2 v1.9	2m 27s
Test GNUStep with libobjc2 v1.9	2m 7s
Test GNUStep with libobjc2 v2.0	2m 47s
Test GNUStep with libobjc2 v2.0	2m 33s
Test GNUStep with libobjc2 v2.1 on nightly	2m 47s
Test GNUStep with libobjc2 v2.1 on nightly	3m 29s
Test GNUStep 32bit	2m 44s
Test GNUStep 32bit	2m 39s
Compiler UI	1m 30s
Compiler UI	1m 30s
${{ matrix.name }}	0s
${{ matrix.name }}	0s
Test on iOS simulator w. dinghy	0s
Test on iOS simulator w. dinghy	0s
	1h 16m 13s

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