pelican: Disable pandoc support for now

Version 3.7.1 is not compatible with the current (more recent) pandoc version.
Since pandoc support is optional in pelican, we can ship it without pandoc
support until a fix will be applied upstream.

Kept a note in the buildInputs so that the improvement opportunity can be
spotted again on future updates of pelican.

pkgs/development/python-modules/pelican/default.nix

@@ -25,7 +25,10 @@ buildPythonPackage rec {
 
   buildInputs = [
     glibcLocales
-    pandoc
+    # Note: Pelican has to adapt to a changed CLI of pandoc before enabling this
+    # again. Compare https://github.com/getpelican/pelican/pull/2252.
+    # Version 3.7.1 is incompatible with our current pandoc version.
+    # pandoc
     git
     mock
     nose