docs(gh): replace gitter with gh discussions

Author: clason

.github/ISSUE_TEMPLATE/config.yml

@@ -1,6 +1,6 @@
 blank_issues_enabled: false
 contact_links:
    - name: Question
-     url: https://gitter.im/nvim-telescope/community
-     about: Usage questions and support requests are answered in the Telescope Gitter
+     url: https://https://github.com/nvim-telescope/telescope.nvim/discussions
+     about: Usage questions, support requests, and general discussions