Add state attribute translations for calendars (#89811)

homeassistant/components/calendar/strings.json

@@ -5,6 +5,26 @@
       "state": {
         "off": "[%key:common::state::off%]",
         "on": "[%key:common::state::on%]"
+      },
+      "state_attributes": {
+        "all_day": {
+          "name": "All day"
+        },
+        "description": {
+          "name": "Description"
+        },
+        "end_time": {
+          "name": "End time"
+        },
+        "location": {
+          "name": "Location"
+        },
+        "messages": {
+          "name": "Message"
+        },
+        "start_time": {
+          "name": "Start time"
+        }
       }
     }
   }