Give the new doc the official number 0024

Author: leonerd

ppcs/ppcTODO-signature-named-parameters.md renamed to ppcs/ppc0024-signature-named-parameters.md

@@ -4,7 +4,7 @@
 
     Author:  Paul Evans <PEVANS>
     Sponsor:
-    ID:      TODO
+    ID:      0024
     Status:  Exploratory
 
 ## Abstract