.github/PR-template: update comment and checklist to discourage AI-generated contributions (#19062)

Co-authored-by: Managor <[email protected]>
Co-authored-by: Seth Falco <[email protected]>

Author: 3 people

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,15 +1,16 @@
 <!--
 Thank you for contributing!
 Please fill in the following checklist, removing items that do not apply.
-See also https://github.com/tldr-pages/tldr/blob/main/CONTRIBUTING.md
+See also https://github.com/tldr-pages/tldr/blob/main/CONTRIBUTING.md.
 -->
 
-#### If you are a new contributor to the project, do not use AI to generate pages. We will close any PR with a suspicion of AI usage.
+### Checklist
 
 - [ ] The page(s) are in the correct platform directories: `common`, `linux`, `osx`, `windows`, `sunos`, `android`, etc.
 - [ ] The page description(s) have links to documentation or a homepage.
 - [ ] The page(s) follow the [content guidelines](/tldr-pages/tldr/blob/main/CONTRIBUTING.md#guidelines).
 - [ ] The page(s) follow the [style guide](/tldr-pages/tldr/blob/main/contributing-guides/style-guide.md).
 - [ ] The PR contains at most 5 new pages.
+- [ ] The PR is authored by me, or has been human-reviewed if it was created with AI or machine translation software.
 - [ ] The PR title conforms to the recommended [templates](/tldr-pages/tldr/blob/main/CONTRIBUTING.md#commit-message-and-pr-title).
 - **Version of the command being documented (if known):**

CONTRIBUTING.md

@@ -31,6 +31,11 @@ To get started, please [sign](https://cla-assistant.io/tldr-pages/tldr) the
 > [!NOTE]
 > When submitting a new command, please base your PR against the `main` branch and check if there's already a pull request in progress for it.
 
+> [!WARNING]
+> We strongly discourage using generative AI tools to create new pages, as their output is often inaccurate and may not follow our style guidelines.
+> For translations, machine translation tools may be used as reference, but their results must be thoroughly proofread before submission.
+> Pull requests suspected of being made in whole or in part through generative AI or machine translation software without human-review will be closed.
+
 ## Guidelines
 
 The basic format of a `tldr` page is a set of concrete usage examples.