This is the UI specification of #2634

[...] is a toggle button.

• When no arguments are present, set it to untoggled.
• When no arguments are present and it's clicked, add $macroArg.1
• When at least an argument is present, set it to toggled.
• When at least an argument is present and it's clicked, don't do anything.
• Make the tooltip "Add macro argument" when it's untoggled.

When a macroArg.* minus button is clicked, remove the relevant macro argument and recalculate the macroArg.* numbers so that they start with 1 and increase one by one. Make its tooltip "Remove macro argument"

Only use a single macroArg.* plus button for the last macro argument. When clicked, add a new argument after the last one. Make its tooltip "Add macro argument"

Render macro key actions to include their arguments, such as "myMacro arg1 arg2"