Show more info in the minimal callback for unreachable hosts

Fixes #12621

lib/ansible/plugins/callback/minimal.py

@@ -74,7 +74,7 @@ class CallbackModule(CallbackBase):
         self._display.display("%s | SKIPPED" % (result._host.get_name()), color='cyan')
 
     def v2_runner_on_unreachable(self, result):
-        self._display.display("%s | UNREACHABLE!" % result._host.get_name(), color='yellow')
+        self._display.display("%s | UNREACHABLE! => %s" % (result._host.get_name(), self._dump_results(result._result, indent=4)), color='yellow')
 
     def v2_on_file_diff(self, result):
         if 'diff' in result._result and result._result['diff']: