use global contributing guide

Remove the per-project files so we don't have to
keep them in sync. GitHub's UI links to everything
except the contributing guide, so add a section
about that to the readme.

(cherry picked from commit 60a11a7)

.github/ISSUE_TEMPLATE/config.yml

@@ -3,9 +3,9 @@ contact_links:
   - name: Security issue
     url: https://github.com/pallets/flask/security/advisories/new
     about: Do not report security issues publicly. Create a private advisory.
-  - name: Questions
+  - name: Questions on GitHub Discussions
     url: https://github.com/pallets/flask/discussions/
     about: Ask questions about your own code on the Discussions tab.
-  - name: Questions on
+  - name: Questions on Discord
     url: https://discord.gg/pallets
     about: Ask questions about your own code on our Discord chat.

README.md

@@ -41,3 +41,11 @@ allow the maintainers to devote more time to the projects, [please
 donate today].
 
 [please donate today]: https://palletsprojects.com/donate
+
+## Contributing
+
+See our [detailed contributing documentation][contrib] for many ways to
+contribute, including reporting issues, requesting features, asking or answering
+questions, and making PRs.
+
+[contrib]: https://palletsprojects.com/contributing/

docs/contributing.rst

@@ -1 +1,8 @@
-.. include:: ../CONTRIBUTING.rst
+Contributing
+============
+
+See the Pallets `detailed contributing documentation <_contrib>`_ for many ways
+to contribute, including reporting issues, requesting features, asking or
+answering questions, and making PRs.
+
+.. _contrib: https://palletsprojects.com/contributing/