Fix help text for Concise test option

Libraries/Gast/CommandLine.icl

@@ -76,7 +76,7 @@ where
 			, "MaxDepth N:         the maximum tree depth in generated test cases"
 			, "Output options:"
 			, "- Quiet:            only show the end result"
-			, "- Concise:          show a test counter"
+			, "- Concise N:        show a test counter for every N tests"
 			, "- Verbose:          show every test case, then hide it again"
 			, "- Trace:            show every test case"
 			, "- OutputTestEvents: output JSON test events as in Testing.TestEvents"