Document revocation parameter formats

Author: RocketPuppy

doc/api/endpoint_revoke.txt

@@ -5,10 +5,10 @@ Method:   POST
 
 Required parameters:
 
-    * serial: a string specifying the serial number of a certificate
+    * serial: a string specifying the serial number of a certificate in decimal format
     * authority_key_id: a string specifying the authority key identifier
       of the certificate to be revoked; this is used to distinguish
-      which private key was used to sign the certificate.
+      which private key was used to sign the certificate. Should be formatted without colons and all lowercase.
     * reason: a string identifying why the certificate was revoked; see,
       for example, ReasonStringToCode in the ocsp package or section
       4.2.1.13 of RFC 5280. The "reasons" used here are the ReasonFlag
@@ -21,6 +21,6 @@ Result:
 Example:
 
     $ curl -d '{"serial": "7961067322630364137",        \
-            "authority_key_id": "00:01:02:03:04:05:07",              \
+            "authority_key_id": "a0b1c2d3e4f5",              \
             "reason": "superseded"}'                    \
           ${CFSSL_HOST}/api/v1/cfssl/revoke