Improve wording relating to removal of MBEDTLS_ERR_SSL_BAD_HS_XXX

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index 1546f4d..65b868a 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -945,7 +945,7 @@
 - `MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN` and `MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE` have been
   replaced by `MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE`.
 
-- All codes of the form `MBEDTLS_ERR_SSL_BAD_HS_XXX` have been replaced by various alternatives.
+- All codes of the form `MBEDTLS_ERR_SSL_BAD_HS_XXX` have been replaced by various alternatives, which give more information about the type of error raised.
 
   Users should check for the newly introduced generic error codes