Fix and improve Ident (RFC 1413) code #860

Job	Run time
functionality-tests	17m 19s
source-maintenance-tests	3m 2s
build-tests(ubuntu-22.04,gcc,default)	11m 19s
CodeQL-tests	35m 44s
build-tests(ubuntu-22.04,gcc,minimal)	6m 16s
build-tests(ubuntu-22.04,gcc,maximus)	13m 33s
build-tests(ubuntu-22.04,clang,default)	14m 3s
build-tests(ubuntu-22.04,clang,minimal)	7m 50s
build-tests(ubuntu-22.04,clang,maximus)	15m 44s
build-tests(macos-14,clang,default)	12m 56s
build-tests(macos-14,clang,minimal)	8m 51s
build-tests(macos-14,clang,maximus)	15m 59s
	2h 42m 36s

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