Encourage +1's for prioritisation

Adds a small text to each issue and the PR template to encourage people to use
:+1:'s for issues they're also interested in. See
https://github.com/NixOS/nix.dev/issues/359 for more information

Co-Authored-By: Valentin Gagarin <valentin.gagarin@tweag.io>

+7
.github/ISSUE_TEMPLATE/bug_report.md
···
[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
output here
```
+
+
### Priorities
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+7
.github/ISSUE_TEMPLATE/build_failure.md
···
[user@system:~]$ nix-shell -p nix-info --run "nix-info -m"
output here
```
+
+
### Priorities
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+6
.github/ISSUE_TEMPLATE/missing_documentation.md
···
[open documentation issues]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+label%3A%229.needs%3A+documentation%22
[open documentation pull requests]: https://github.com/NixOS/nixpkgs/pulls?q=is%3Aopen+is%3Apr+label%3A%228.has%3A+documentation%22%2C%226.topic%3A+documentation%22
+
### Priorities
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+7
.github/ISSUE_TEMPLATE/out_of_date_package_report.md
···
-----
Note for maintainers: Please tag this issue in your PR.
+
+
**Priorities**
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+7
.github/ISSUE_TEMPLATE/packaging_request.md
···
* source URL:
* license: mit, bsd, gpl2+ , ...
* platforms: unix, linux, darwin, ...
+
+
**Priorities**
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+7
.github/ISSUE_TEMPLATE/unreproducible_package.md
···
(please share the relevant fragment of the diffoscope output here, and any
additional analysis you may have done)
+
+
### Priorities
+
+
Add a :+1: [reaction] to [issues you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc
+7
.github/PULL_REQUEST_TEMPLATE.md
···
List of open PRs: https://github.com/NixOS/nixpkgs/pulls
Reviewing guidelines: https://nixos.org/manual/nixpkgs/unstable/#chap-reviewing-contributions
-->
+
+
### Priorities
+
+
Add a :+1: [reaction] to [pull requests you find important].
+
+
[reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/
+
[pull requests you find important]: https://github.com/NixOS/nixpkgs/pulls?q=is%3Aopen+sort%3Areactions-%2B1-desc