all: standardize RFC mention format

Standardize on space between "RFC" and number. Additionally change
the couple "a RFC" instances to "an RFC."

Fixes #15258

Change-Id: I2b17ecd06be07dfbb4207c690f52a59ea9b04808
Reviewed-on: https://go-review.googlesource.com/21902
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

common.go

@@ -114,7 +114,7 @@ const (
 	certTypeRSAFixedDH = 3 // A certificate containing a static DH key
 	certTypeDSSFixedDH = 4 // A certificate containing a static DH key
 
-	// See RFC4492 sections 3 and 5.5.
+	// See RFC 4492 sections 3 and 5.5.
 	certTypeECDSASign      = 64 // A certificate containing an ECDSA-capable public key, signed with ECDSA.
 	certTypeRSAFixedECDH   = 65 // A certificate containing an ECDH-capable public key, signed with RSA.
 	certTypeECDSAFixedECDH = 66 // A certificate containing an ECDH-capable public key, signed with ECDSA.

prf.go

@@ -85,7 +85,7 @@ func prf30(result, secret, label, seed []byte) {
 
 	done := 0
 	i := 0
-	// RFC5246 section 6.3 says that the largest PRF output needed is 128
+	// RFC 5246 section 6.3 says that the largest PRF output needed is 128
 	// bytes. Since no more ciphersuites will be added to SSLv3, this will
 	// remain true. Each iteration gives us 16 bytes so 10 iterations will
 	// be sufficient.