Update persons query

aleksis/apps/alsijil/frontend/components/coursebook/absences/absenceCreation.graphql

-# Use core persons query
+# Uses core persons query
 query persons {
   persons: persons {
     id
-    name
+    firstName
+    lastName
   }
 }
 
@@ -36,7 +37,7 @@ query lessonsForPersons(
   }
 }
 
-# Use absencesInputType
+# Use absencesInputType?
 mutation createAbsences(
   $persons: [ID!]!
   $start: Date!