PULL_REQUEST_TEMPLATE

Standards checklist:

<!-- Fill with an x the ones that apply. Example: [x] -->

• [ ] The PR title is descriptive.
• [ ] The PR doesn't replicate another PR which is already open.
• [ ] I have read the contribution guide and followed all the instructions.
• [ ] The code follows the code style guide detailed in the wiki.
• [ ] The code is mine or it's from somewhere with an MIT-compatible license.
• [ ] The code is efficient, to the best of my ability, and does not waste computer resources.
• [ ] The code is stable and I have tested it myself, to the best of my abilities.
• [ ] If the code introduces new aliases, I provide a valid use case for all plugin users down below.

Changes:

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