Improve clarity of xmldoc

Co-authored-by: Dan Balasescu <smoogipoo@smgi.me>

osu.Game/Database/IRealmFactory.cs

@@ -13,7 +13,7 @@ public interface IRealmFactory
         Realm Context { get; }
 
         /// <summary>
-        /// Create a new realm context for use on an arbitrary thread.
+        /// Create a new realm context for use on the current thread.
         /// </summary>
         Realm CreateContext();
     }