Remove duplicate line. (#25716)

manual/en/post-processing-3dlut.html

@@ -180,7 +180,6 @@ composer.addPass(renderBG);
 composer.addPass(renderModel);
 composer.addPass(effectLUT);
 composer.addPass(effectLUTNearest);
-composer.addPass(effectLUTNearest);
 composer.addPass(gammaPass);
 </pre>
 <p>Let's make some GUI code to select one lut or the other</p>