Add explicit Commitment Input syntax requirement

tips/TIP-0045/tip-0045.md

@@ -1190,6 +1190,7 @@ The following criteria defines whether a payload passes the syntactical validati
       - `Index` as the second criteria for _Reward Inputs_.
       - `Account ID` as the second criteria for _Block Issuance Credit Inputs_.
     - There must be zero or one _Commitment Input_.
+    - A _Commitment Input_ must be present if one or more _Block Issuance Credit Inputs_ or _Reward Inputs_ are present.
     - For each `Index` in the _Reward Inputs_ it must hold that: `Index < Inputs Count`.
   - Outputs:
     - `Outputs Count` must be `0 < x ≤ Max Outputs Count`.