Document built-in bridge configuration

Signed-off-by: James Rhodes <[email protected]>

crates/common/tedge_config/src/tedge_config_cli/tedge_config.rs

@@ -769,6 +769,9 @@ define_tedge_config! {
 
         bridge: {
             #[tedge_config(default(value = false))]
+            #[tedge_config(example = "false")]
+            #[tedge_config(note = "After changing this value, run `tedge reconnect <cloud>` to apply the changes")]
+            /// Enables the built-in bridge when running tedge-mapper
             built_in: bool,
 
             reconnect_policy: {