Refer to RFCs consistently.

We were a mix of "RFC1234" and "RFC 1234". Apparently there is actually
an answer for this, which is with a space textually and without a space
in the citation/reference tag:
https://datatracker.ietf.org/doc/html/rfc7322#section-3.5

Change-Id: I0c44023163fe3a2a3ffe28cbc644d4c952dc8f1e
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/48965
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/x509/x509_test.cc b/crypto/x509/x509_test.cc
index d2813fa..0e64018 100644
--- a/crypto/x509/x509_test.cc
+++ b/crypto/x509/x509_test.cc
@@ -3059,7 +3059,7 @@
 
 // Test the various |X509_ATTRIBUTE| creation functions.
 TEST(X509Test, Attribute) {
-  // The friendlyName attribute has a BMPString value. See RFC2985,
+  // The friendlyName attribute has a BMPString value. See RFC 2985,
   // section 5.5.1.
   static const uint8_t kTest1[] = {0x26, 0x03};  // U+2603 SNOWMAN
   static const uint8_t kTest1UTF8[] = {0xe2, 0x98, 0x83};