Rewrite CamelCase keys to underscore on the Python `eqJoin` docs
Rewrite CamelCase keys to underscore on the Python `eqJoin` docs

rust-rethinkdb/reql,rust-rethinkdb/reql,rust-rethinkdb/reql,rust-rethinkdb/reql,rust-rethinkdb/reql,rust-rethinkdb/reql