chore: add discussions to issue template

Now that GitHub discussions have been enabled
(see https://github.com/nvim-lua/kickstart.nvim/issues/2026),
add links in the issue template to help redirect help/feature requests
from the bug tracker.

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,10 @@
+blank_issues_enabled: false
+
+contact_links:
+  - name: Help
+    url: https://github.com/nvim-lua/kickstart.nvim/discussions/categories/q-a
+    about: Ask the community for help
+
+  - name: Ideas
+    url: https://github.com/nvim-lua/kickstart.nvim/discussions/categories/ideas
+    about: Share ideas for new features