Be more vocal about indexing errors

Hello,

first of all, thanks guys for the amazing module!

i just realized i was mistakenly trying to put different entities in the same index, so getting this error:

Elasticsearch indexing failed: {"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"Rejecting mapping update to [multilingual-en] as the final mapping would have more than 1 type: [node, my_entity]"}],"type":"illegal_argument_exception","reason":"Rejecting mapping update to [multilingual-en] as the final mapping would have more than 1 type: [node, my_entity]"},"status":400}

not cool! the thing is that i could only see this error if i went looking at the drupal logs. Could this be more vocal instead?