fix top-level comments

R=rsc
DELTA=14  (13 added, 0 deleted, 1 changed)
OCL=17858
CL=17867

src/lib/fmt/format.go

@@ -5,10 +5,12 @@
 package fmt
 
 /*
+	Raw formatter. See print.go for a more palatable interface.
+
 	f := fmt.New();
 	print f.d(1234).s("\n").str();  // create string, print it
 	f.d(-1234).s("\n").put();  // print string
-	f.ud(^0).putnl();  // print string with automatic newline
+	f.ud(1<<63).putnl();  // print string with automatic newline
 */
 
 // export Fmt, New;

src/lib/fmt/print.go

@@ -4,6 +4,11 @@
 
 package fmt
 
+/*
+	C-like printf, but because of reflection knowledge does not need
+	to be told about sizes and signedness (no %llud etc. - just %d).
+*/
+
 import (
 	"fmt";
 	"reflect";