Update include/secp256k1_musig.h

Co-authored-by: Elliott Jin <[email protected]>

Author: jonasnick

include/secp256k1_musig.h

@@ -434,7 +434,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_partial_sig_verif
  *  In:       session: pointer to the session that was created with
  *                     musig_nonce_process
  *       partial_sigs: array of pointers to partial signatures to aggregate
- *             n_sigs: number of elements in the partial_sigs array
+ *             n_sigs: number of elements in the partial_sigs array. Must be
+ *                     greater than 0.
  */
 SECP256K1_API int secp256k1_musig_partial_sig_agg(
     const secp256k1_context* ctx,