chore(doc): Update feature flag document about transport and channel

Author: tottoto

tonic/src/lib.rs

@@ -16,10 +16,9 @@
 //!
 //! # Feature Flags
 //!
-//! - `transport`: Enables the fully featured, batteries included client and server
-//!     implementation based on [`hyper`], [`tower`] and [`tokio`]. Enabled by default.
-//! - `channel`: Enables just the full featured channel/client portion of the `transport`
-//!     feature.
+//! - `transport`: Enables just the full featured server portion of the `channel` feature.
+//! - `channel`: Enables the fully featured, batteries included client and server
+//! implementation based on [`hyper`], [`tower`] and [`tokio`]. Enabled by default.
 //! - `codegen`: Enables all the required exports and optional dependencies required
 //! for [`tonic-build`]. Enabled by default.
 //! - `tls`: Enables the `rustls` based TLS options for the `transport` feature. Not