add english desc

i18n/en.i18n.json

@@ -137,6 +137,8 @@
     "color-yellow": "yellow",
     "comment": "Comment",
     "comment-placeholder": "Write a comment",
+    "comment-only": "Comment",
+    "comment-only-desc": "Can only comment on cards on this board, nothing else.",
     "computer": "Computer",
     "create": "Create",
     "createBoardPopup-title": "Create Board",
@@ -345,4 +347,4 @@
     "email-invite-register-subject": "__inviter__ sent you an invitation",
     "email-invite-register-text": "Dear __user__,\n\n__inviter__ invites you to Wekan for collaborations.\n\nPlease follow the link below:\n__url__\n\nAnd your invitation code is: __icode__\n\nThanks.",
     "error-invitation-code-not-exist": "Invitation code doesn't exist"
-}
+}