[chore][docs] Reflect current practices about configuration structs in coding guidelines #27997

Job	Run time
contrib-tests-matrix (receiver-0)	2m 15s
contrib-tests-matrix (receiver-1)	2m 15s
contrib-tests-matrix (receiver-2)	2m 17s
contrib-tests-matrix (receiver-3)	2m 16s
contrib-tests-matrix (processor)	2m 17s
contrib-tests-matrix (exporter-0)	2m 18s
contrib-tests-matrix (exporter-1)	2m 17s
contrib-tests-matrix (extension)	2m 19s
contrib-tests-matrix (connector)	2m 18s
contrib-tests-matrix (internal)	2m 18s
contrib-tests-matrix (pkg)	2m 18s
contrib-tests-matrix (cmd-0)	53s
contrib-tests-matrix (cmd-1)	1m 23s
contrib-tests-matrix (other)	2m 17s
contrib_tests	1s
	29m 42s

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