add notes about module interface implementations

src/content/docs/modules/db/sqlite.mdx

@@ -10,6 +10,8 @@ The `db.sqlite` module can open/create SQLite databases
 - **params**:
   - **dsn**: the data source name, this can be a file path or the special `:memory:` name for an in-memory DB
 
+This module implements the `DatabaseModule` interface.
+
 ## Cap
 
 ### Example snippet

src/content/docs/modules/mqtt/client.mdx

@@ -13,6 +13,8 @@ The `mqtt.client` module connects to a MQTT broker and emits a message messages
   - **topic** mqtt topic to subscribe to
   - **clientId** client ID for this connection to the broker
 
+This module implements the `PubSubModule` interface.
+
 ### Example
 
 Open a mqtt connection to `test.mosquitto.org` subscribing to the `showbridge` topic.

src/content/docs/modules/nats/client.mdx

@@ -12,6 +12,8 @@ This module connects to a [NATS](https://nats.io/) server and subscribes to a su
   - **url**: the URL of the NATS server to connect to (e.g. `nats://localhost:4222`)
   - **subject**: the subject to subscribe to
 
+This module implements the `PubSubModule` interface.
+
 ### Example
 
 Connect to a local NATS server and subscribe to the `events` subject

src/content/docs/modules/redis/client.mdx

@@ -12,6 +12,8 @@ The `redis.client` module connects to a Redis server. This module does not produ
   - **host**: the Redis server host
   - **port**: the Redis server port
 
+This module implements the `KeyValueModule` interface.
+
 ### Example
 
 Connect to a Redis server running on `localhost` at port `6379`.