Don't allow psa_xxx() to return MBEDTLS_ERR_XXX

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/error-unification.txt b/ChangeLog.d/error-unification.txt
index a19e60c..bcf5ba1 100644
--- a/ChangeLog.d/error-unification.txt
+++ b/ChangeLog.d/error-unification.txt
@@ -1,10 +1,10 @@
 API changes
-   * The PSA and Mbed TLS error space are now unified. This means that
-     mbedtls_xxx() functions can return PSA_ERROR_xxx values.
+   * The PSA and Mbed TLS error spaces are now unified. mbedtls_xxx()
+     functions can now return PSA_ERROR_xxx values.
      There is no longer a distinction between "low-level" and "high-level"
-     Mbed TLS error codes..
-     This will not affect most applications since in both cases, the
-     error values are between -32767 and -1 as before.
+     Mbed TLS error codes.
+     This will not affect most applications since the error values are
+     between -32767 and -1 as before.
 
 Removals
    * Remove mbedtls_low_level_sterr() and mbedtls_high_level_strerr(),