In bash, if I have a command on the line, and I press Alt-# (with the cursor anywhere on the line), it adds a
# to the front of the line, commenting it out, 'executes' it (which does nothing since it's now commented out), and puts it into the history. It's really useful for when I type some or all of a command and realise I need to run another command first and come back to that one later.
How can I do the same operation in zsh? The commenting-out isn't important: all I care about is that the command doesn't happen right now, but can be retrieved from history later.