Bug 1551689 - Print listener address with a new-line. r=remote-protocol-reviewers,ato

Differential Revision: https://phabricator.services.mozilla.com/D31127

--HG--
extra : moz-landing-system : lando

remote/RemoteAgent.jsm

@@ -100,7 +100,7 @@ class RemoteAgentClass {
       const mainTarget = this.targets.getMainProcessTarget();
 
       this.server._start(port, host);
-      dump(`DevTools listening on ${mainTarget.wsDebuggerURL}`);
+      dump(`DevTools listening on ${mainTarget.wsDebuggerURL}\n`);
     } catch (e) {
       throw new Error(`Unable to start remote agent: ${e.message}`, e);
     }