Fixed language source typo

i18n/en.i18n.json

@@ -576,7 +576,7 @@
     "r-checklist": "checklist",
     "r-check-all": "Check all",
     "r-uncheck-all": "Uncheck all",
-    "r-item-check": "Items of checklist",
+    "r-items-check": "items of checklist",
     "r-check": "Check",
     "r-uncheck": "Uncheck",
     "r-item": "item",