PSA PAKE: Clarify J-PAKE algorithm documentation

- Transformed setup description to a more explicit pseudocode based
approach.
- Explained implicit vs explicit key confirmation

Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index abf3da0..2fe797a 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -4350,7 +4350,7 @@
  * \retval #PSA_ERROR_STORAGE_FAILURE
  * \retval #PSA_ERROR_NOT_PERMITTED
  * \retval #PSA_ERROR_INVALID_ARGUMENT
- *         \p key is not compatible with the algorithm in \p cipher_suite.
+ *         \p key is not compatible with the algorithm or the cipher suite.
  * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize
@@ -4407,6 +4407,8 @@
  * \retval #PSA_ERROR_NOT_PERMITTED
  *         One of the inputs to \p key_derivation was a key whose policy didn't
  *         allow #PSA_KEY_USAGE_DERIVE.
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ *         \p key is not compatible with the algorithm or the cipher suite.
  * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize