(Doc) Kafka Connect configuration document is inconsistent with implementation

[hsiang-c]

Problem Description

• In the official doc, one of the rules to convert property variables to environment variables is

  Replace a dash (-) with double underscores (__).

• However, the env_to_props method in dub.py does the reverse conversion differently

  three underscores '___' are replaced with a dash '-'

Validation

• I tested it with confluentinc/cp-kafka-connect:7.5.1 and I think the official doc might be wrong, i.e. a dash (-) should be replaced by three underscores instead of double underscores.