Change declare_class! syntax #3145

Job	Run time
Check MSRV	46s
Lint macOS x86_64	2m 35s
Check formatting	10s
Lint iOS ARMv7s	2m 23s
Lint visionOS Aarch64 simulator	2m 21s
Lint GNUStep + exceptions	1m 29s
Lint header-translator	29s
Lint test-assembly	31s
Test macOS 15 Aarch64	1m 27s
Assembly tests	3m 49s
Verify header translator output	53s
Test macOS 13 x86_64	1m 15s
Check framework features	4m 31s
Test macOS 15 AArch64	1s
Test Compiler-RT	24s
Test macOS 14 Aarch64 nightly	1s
Test GNUStep with libobjc2 v1.9	2m 8s
Build macOS 13 x86 with 10.13 SDK	1s
Test GNUStep with libobjc2 v2.0	2m 8s
Test on iOS simulator w. dinghy	39m 35s
Compiler UI	43s
Test macOS 13 x86_64 with 10.12 SDK	1s
Test GNUStep with libobjc2 v2.1 on nightly	1m 49s
Test GNUStep 32bit	1m 51s
Build iOS x86_64 simulator	2m 5s
Test Mac Catalyst Aarch64	1m 40s
Build visionOS Aarch64	1s
Build tvOS Aarch64	1s
Build watchOS ARM64_32	1s
Build iOS ARMv7s	3m 23s
Build iOS x86	3m 17s
	1h 21m 49s

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