fix some file extensions

Task/Gray-code/DWScript/gray-code.dw

@@ -0,0 +1,23 @@
+function Encode(v : Integer) : Integer;
+begin
+   Result := v xor (v shr 1);
+end;
+
+function Decode(v : Integer) : Integer;
+begin
+   Result := 0;
+   while v>0 do begin
+      Result := Result xor v;
+	  v := v shr 1;
+   end;
+end;
+
+PrintLn('decimal  binary   gray    decoded');
+
+var i : Integer;
+for i:=0 to 31 do begin
+   var g := Encode(i);
+   var d := Decode(g);
+   PrintLn(Format('  %2d     %s   %s   %s  %2d',
+                  [i, IntToBin(i, 5), IntToBin(g, 5), IntToBin(d, 5), d]));
+end;