Docs: Note that plugin removal usually requires node restart
Docs: Note that plugin removal usually requires node restart

Closes #13301
Closes #13983

baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo,baishuo/elasticsearch_v2.1.0-baishuo