Instrumentation kafka docs malformed with wrong rst blocks

[emdneto]

Some documentations are broken with wrong rst blocks, specially related to kafka

https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/aiokafka/aiokafka.html
https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/confluent_kafka/confluent_kafka.html
https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/kafka_python/kafka_python.html

Originally posted by @emdneto in #3060 (review)

[Shiravani24]

would like to work on this issue.

[buger]

@Shiravani24 sorry I already submitted PR..

@emdneto hope its ok, I also improved examples to be more end to end.

PS. Found this ticket via https://helpwanted.dev/