Send typing to multiple panes, ala 'synchronize-panes' in tmux

[fcpg]

Is your feature request related to a problem? Please describe.
A nice feature in tmux is the synchronize-panes window option, that duplicate input to all panes in the current tab. Quite handy when you need to run some commands on several hosts - just open a pane for each host, ssh into it, and turn the option on. All keystrokes are sent to every panes. Turn option off when you're done.

Describe the solution you'd like
A toggle option/command similar to synchronize-panes.

Describe alternatives you've considered
Well, ansible can solve the same kind of problems, but it's far from always available. synchronize-panes is more crude but very handy when you need it.

Additional context
N/A

[wez]

Duplicate of #2658

[github-actions]

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