feeds: document the Nonlinear Library

hosts/common/feeds.nix

@@ -1,3 +1,7 @@
+# candidates:
+# - The Nonlinear Library (podcast): <https://forum.effectivealtruism.org/posts/JTZTBienqWEAjGDRv/listen-to-more-ea-content-with-the-nonlinear-library>
+#   - has ~10 posts per day, text-to-speech; i would need better tagging before adding this
+
 { lib, sane-data, ... }:
 let
   hourly = { freq = "hourly"; };