preserveComments doesn't work

Describe the bug
The compiler option preserveComments: true does nothing.

To Reproduce
See this repo. With minimal changes from the svelte/template. This is my output with missing comment.

Expected behavior
Keep the comment in the SSR.

Probably this is because of this todo:

Lines 5 to 9 in aabb23c

     // TODO preserve comments  
    
   // if (options.preserveComments) {  
   //	renderer.append(`<!--${node.data}-->`);  
   // }  
 

Information about your Svelte project:
svelte-3.21.0 & rollup.

Provide feedback

	// TODO preserve comments

	// if (options.preserveComments) {
	// renderer.append(`<!--${node.data}-->`);
	// }