Add `close_tab` keybinding action

[mitchellh]

Discussed in #3778

^{Originally posted by Qtechinnovation December 28, 2024}
I noticed that https://ghostty.org/docs/config/keybind/reference does not mention an option to set a keybind to close a tab, but only to open one. I assumed that since opening a new tab by default uses the rather sensible ctrl+shift+t, that closing the tab would use ctrl+shift+w, but it does not. Is there an option to set a close tab keybind? I found a discussion about a person who forked ghostty to add one, but no interaction with the discussion, so I think this is warranted, especially for all the people who use keybinds as a way to increase productivity.

Details

This would close a tab and all splits within that tab. This should behave like close_window does for tabs and splits.

[FinleyGe]

In fact, there is a option close_surface to close the "surface": split, tab or windows.
This option could be helpful.

[lg28literconvectionmicrowaveoven]

implementation for the gtk apprt: #4033