Fix documentation of macro '%-x'

docs/manual/macros.md

@@ -38,7 +38,7 @@ macros are available:
 	%*	all arguments (unlike shell, not including any processed flags)
 	%**	all arguments (including any processed flags)
 	%#	the number of arguments
-	%{-f}	if present at invocation, the flag f itself
+	%{-f}	if present at invocation, the flag f itself (including the argument)
 	%{-f*}	if present at invocation, the argument to flag f
 	%1, %2	the arguments themselves (after getopt(3) processing)
 ```