Add missing comment to bower.fish

Same comment found in yarn.fish

share/completions/bower.fish

@@ -51,6 +51,7 @@ function __bower_list_installed
     end
 
     if set -l python (__fish_anypython)
+        # Warning: That weird indentation is necessary, because python.
         $python -c 'import json, sys; data = json.load(sys.stdin);
 for k,v in data["dependencies"].items(): print(k + "\t" + v[:18])' bower.json 2>/dev/null
         return