private String description(UsageMessageSpec usageMessage) {
			if (usageMessage.header().length > 0) {
				return usageMessage.header()[0];
			}
			if (usageMessage.description().length > 0) {
				return usageMessage.description()[0];
			}
			return "";
		}
validate all commands in Help is covered by section and each section command
exist in help.

@param help
src/main/java/dev/jbang/cli/JBang.java