[BestPractices Removing micro-optimization note about @Template

| Q   | A
| --- | ---
| Doc fix? | no
| New docs? | no
| Applies to | 2.3+
| Fixed tickets | -

Hi guys!

I think that a small performance gain is not a *great* reason to recommend something. And really, this was not the most important reason for recommending against `@Template`. I think it's clearer to focus on the real reason, and not get into performance (we could argue against using any feature because of performance).

Thanks!
I don't have profiling data, so this is just a guess: the culprit could be [TemplateGuesser](https://github.com/sensiolabs/SensioFrameworkExtraBundle/blob/master/Templating/TemplateGuesser.php) which looks heavy and it evens use reflection.