src: add linebreak to inspector message

Add linebreak to inspector ready message to wrap properly in
80 column (default) terminal windows.

Fixes: https://github.com/nodejs/node/issues/7067
PR-URL: https://github.com/nodejs/node/pull/7070
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Claudio Rodriguez <cjrodr@yahoo.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

src/inspector_agent.cc

@@ -31,7 +31,7 @@ namespace {
 const char DEVTOOLS_PATH[] = "/node";
 
 void PrintDebuggerReadyMessage(int port) {
-  fprintf(stderr, "Debugger listening on port %d. "
+  fprintf(stderr, "Debugger listening on port %d.\n"
     "To start debugging, open the following URL in Chrome:\n"
     "    chrome-devtools://devtools/remote/serve_file/"
     "@521e5b7e2b7cc66b4006a8a54cb9c4e57494a5ef/inspector.html?"