[CC-1470] Add C23 to interpreter #268

Job	Run time
test_course_definition / go_lint	2s
test_course_definition / identify_language_slugs	3s
test_course_definition / js_lint	23s
test_course_definition / docker_lint	9s
test_course_definition / lint	58s
test_course_definition / rust_lint	6s
test_course_definition / validate-schemas	18s
test_course_definition / markdown_lint	1m 0s
test_course_definition / verify_templates_compiled	21s
test_course_definition / validate-stages-naming	5s
test_course_definition / test (c)	2m 0s
test_course_definition / test (gleam)	41s
test_course_definition / test (go)	1m 2s
test_course_definition / test (javascript)	36s
test_course_definition / test (kotlin)	1m 55s
test_course_definition / test (ocaml)	2m 15s
test_course_definition / test (python)	40s
test_course_definition / test (rust)	57s
test_course_definition / test (swift)	1m 11s
test_course_definition / test (zig)	1m 11s
	15m 53s

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