youtube-tui: docs: mention more invidious instances

hosts/common/programs/youtube-tui.nix

@@ -1,7 +1,9 @@
 # repo: <https://github.com/Siriusmart/youtube-tui>
 # troubleshooting:
 # - "Invalid Request: This helps protect our community."
-#   - choose a different invidious instance (https://farside.link/)
+#   - choose a different invidious instance
+#     - <https://docs.invidious.io/instances/>
+#     - <https://farside.link/>
 #   - <https://github.com/Siriusmart/youtube-tui/issues/57>
 # thumbnail `images` options:
 # - None