bytes,string: move the BUG to the comment of the function it's about

Avoids printing it every time we ask a question about the package from
the command line.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7789048

src/pkg/bytes/bytes.go

@@ -461,10 +461,10 @@ func isSeparator(r rune) bool {
 	return unicode.IsSpace(r)
 }
 
-// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
-
 // Title returns a copy of s with all Unicode letters that begin words
 // mapped to their title case.
+//
+// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
 func Title(s []byte) []byte {
 	// Use a closure here to remember state.
 	// Hackish but effective. Depends on Map scanning in order and calling

src/pkg/strings/strings.go

@@ -492,10 +492,10 @@ func isSeparator(r rune) bool {
 	return unicode.IsSpace(r)
 }
 
-// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
-
 // Title returns a copy of the string s with all Unicode letters that begin words
 // mapped to their title case.
+//
+// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
 func Title(s string) string {
 	// Use a closure here to remember state.
 	// Hackish but effective. Depends on Map scanning in order and calling