Add missing tests and docs for modified query error codes

[a2l007]

As a follow-up to #10746 , additional unit tests for JsonParserIterator are required as well as the query docs(https://druid.apache.org/docs/latest/querying/querying.html) need to be updated with the latest error codes.
Supporting integration tests would be useful as well

[suneet-s]

Added milestone 0.21.0 to this issue, since #10746 is part of the 0.21.0 release