Split Definitions into Parameters and Functions

Author: MarkLodato

specification.md

@@ -41,7 +41,7 @@ The signature format is a JSON message of the following form:
 Empty fields may be omitted. [Multiple signatures](#multiple-signatures) are
 allowed.
 
-Definitions:
+Parameters:
 
 *   SERIALIZED_BODY is the byte sequence to be signed.
 
@@ -60,6 +60,8 @@ Definitions:
 *   KEYID is an optional, unauthenticated hint indicating what key was used to
     sign the message. It **must not** be used for security decisions.
 
+Functions:
+
 *   PAE() is the
     [PASETO Pre-Authentication Encoding](https://github.com/paragonie/paseto/blob/master/docs/01-Protocol-Versions/Common.md#authentication-padding),
     where parameters `type` and `body` are byte sequences: