.github/PULL_REQUEST_TEMPLATE: remove note about reviews

While this note is important, it's also mostly invisible at this stage.
The comment only shows while creating the PR, but at this stage the
author really has other things to worry about.

If they care, they will read the contribution guidelines and will pick
up the pieces about reviewing that way. If they don't - they won't be
bothered by this notice either.

.github/PULL_REQUEST_TEMPLATE.md

@@ -29,17 +29,6 @@ For new packages please briefly describe the package or provide a link to its ho
   - [ ] (Module addition) Added a release notes entry if adding a new NixOS module
 - [ ] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md), [pkgs/README.md](https://github.com/NixOS/nixpkgs/blob/master/pkgs/README.md), [maintainers/README.md](https://github.com/NixOS/nixpkgs/blob/master/maintainers/README.md) and other contributing documentation in corresponding paths.
 
-<!--
-To help with the large amounts of pull requests, we would appreciate your
-reviews of other pull requests, especially simple package updates. Just leave a
-comment describing what you have tested in the relevant package/service.
-Reviewing helps to reduce the average time-to-merge for everyone.
-Thanks a lot if you do!
-
-List of open PRs: https://github.com/NixOS/nixpkgs/pulls
-Reviewing guidelines: https://github.com/NixOS/nixpkgs/blob/master/pkgs/README.md#reviewing-contributions
--->
-
 ---
 
 Add a :+1: [reaction] to [pull requests you find important].