Update src/content/docs/hyperdrive/examples/fly.mdx

Author: thomasgauvin

src/content/docs/hyperdrive/examples/fly.mdx

@@ -54,7 +54,7 @@ You can connect Hyperdrive to any existing Fly database by:
 4. [Obtain the connection string](https://fly.io/docs/postgres/connecting/connecting-external/#adapting-the-connection-string), which is in the form of:
 
 	```txt
-	postgres://{username}:{password}@{hostname}:{port}/{database}?options
+	postgres://{username}:{password}@{public-hostname}:{port}/{database}?options
 	```
 </Steps>