fix hackmd view

resource/locales/en_US/translation.json

@@ -425,7 +425,7 @@
     "open_sandbox": "Open Sandbox"
   },
   "hackmd": {
-    "hackmd": "HackMD",
+    "hack_md": "HackMD",
     "not_set_up": "HackMD is not set up.",
     "start_to_edit": "Start to edit with HackMD",
     "clone_page_content": "Click to clone page content and start to edit.",

resource/locales/ja_JP/translation.json

@@ -427,7 +427,7 @@
     "open_sandbox": "Sandbox を開く"
   },
   "hackmd":{
-    "hackmd": "HackMD",
+    "hack_md": "HackMD",
     "not_set_up": "HackMD はセットアップされていません",
     "start_to_edit": "HackMD を開始する",
     "clone_page_content": "ページを複製して編集を開始します",

resource/locales/zh_CN/translation.json

@@ -396,7 +396,7 @@
 		"open_sandbox": "开放式沙箱"
 	},
 	"hackmd": {
-    "hackmd": "HackMD",
+    "hack_md": "HackMD",
 		"not_set_up": "HackMD is not set up.",
 		"start_to_edit": "Start to edit with HackMD",
 		"clone_page_content": "Click to clone page content and start to edit.",

src/client/js/components/Navbar/GrowiSubNavigation.jsx

@@ -199,7 +199,7 @@ const GrowiSubNavigation = (props) => {
               </button>
               <button type="button" className="btn btn-outline-primary">
                 <i className="fa fa-fw fa-file-text-o" />
-                { t('hackmd') }
+                { t('hackmd.hack_md') }
               </button>
             </div>
           </div>