added description of the IReadFromConfig interface

osu.Game/Rulesets/Mods/IReadFromConfig.cs

@@ -5,6 +5,9 @@ using osu.Game.Configuration;
 
 namespace osu.Game.Rulesets.Mods
 {
+    /// <summary>
+    /// An interface for mods that require reading access to the osu! configuration.
+    /// </summary>
     public interface IReadFromConfig
     {
         void ReadFromConfig(OsuConfigManager config);