Included htm as an alias for html

ColorCode/Compilation/Languages/Html.cs

@@ -125,7 +125,14 @@ namespace ColorCode.Compilation.Languages
 
         public bool HasAlias(string lang)
         {
-            return false;
+            switch (lang.ToLower())
+            {
+                case "htm":
+                    return true;
+
+                default:
+                    return false;
+            }
         }
 
         public override string ToString()