Description
Currently TemplateIterator::findTemplatesInDirectory($dir, $namespace = null) is returning everything from directory because of this line foreach (Finder::create()->files()->followLinks()->in($dir) as $file)

Example
Since this is a template iterator, does it makes sense to filter only template files from directory?Something like this foreach (Finder::create()->name('*.twig')->files()->followLinks()->in($dir) as $file)

This is useful when you want to have in your template directory related assets like *.js or *.css or event whole node_modules directory.

I can provide a PR with unit tests if you want.