Neaten 'Please call next function' docs.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tf-psa-crypto/include/psa/crypto.h b/tf-psa-crypto/include/psa/crypto.h
index 310cfc7..3260620 100644
--- a/tf-psa-crypto/include/psa/crypto.h
+++ b/tf-psa-crypto/include/psa/crypto.h
@@ -4968,9 +4968,9 @@
  *                              required before calling.
  *
  * \retval #PSA_SUCCESS
- *          The operation started successfully - please call \c
- *          psa_key_agreement_iop_complete() with the same context to complete
- *          the operation.
+ *          The operation started successfully.
+ *          Call \c psa_key_agreement_iop_complete() with the same context to
+ *          complete the operation.
  *
  * \retval #PSA_ERROR_BAD_STATE
  *          Another operation has already been started on this context, and is