docs: Clean up link to API docs
//! # influxdb2_client
//!
-//! This is a Rust client to InfluxDB using the 2.0 API.
-//! that implements the API in https://v2.docs.influxdata.com/v2.0/reference/api/
+//! This is a Rust client to InfluxDB using the [2.0 API][2api].
+//!
+//! [2api]: https://v2.docs.influxdata.com/v2.0/reference/api/
//!
//! ## Work Remaining
//!
