[Documentation] Improve backspace issue documentation

[9SMTM6]

Could not categorize this properly. This is about documentation.

I'm talking about this documentation:

https://zellij.dev/documentation/compatibility.html#backspace-sending-ctrl-h-entering-into-move-mode

Which I assume is from this code: https://github.com/zellij-org/zellij-org.github.io/blob/main/docs/src/compatibility.md#backspace-sending-ctrl-h-entering-into-move-mode

There's multiple issues about this: https://github.com/zellij-org/zellij/issues/2289 https://github.com/zellij-org/zellij/issues/1031 https://github.com/zellij-org/zellij/issues/2132

I think this documentation could be greatly improved. As is, after reading it, I was still nowhere close to solving the underlying issue.

Here are some shortcomings:

• with many it isnt backspace sending ^H, but ctrl + backspace
• with at least one popular terminal emulator, Konsole, the character that is send isnt configured with the ANSI excape code, but with the corresponding C-Escape code, meaning for anyone looking at this, its hard to identify the issue.

• the wiki article doesnt even list ^?. And in general. When doing a websearch with ^H etc, I find that search engines refuse to search for this. I have been unable to fix this, with any qualification in front of it, or any quoting. So the ^H doesnt really help in discovering more information. I've yet to find out, what C Escape code I would have to enter into the Konsole config to rebind Ctrl + backspace so zellij doesnt react.
• one last crucial thing. Chances are, that the reason people notice this when its Ctrl + Backspace, is that they have that bound to some other action. So rebinding this combination in your emulator config isnt even going to fix this issue, because then that other application that listens to ^H will just never recieve a signal either. So an complete fix would also include changing the other tool to listen to ^?in whatever language they use, be it C escapes like Konsole, or something else.

The reason I dont just make a pull request, is that at this point I'm not entirely sure on what to change, These are quite a bunch of points, and I'm not entirely sure on all fixes (eg. still have not found a webpage referencing ^? and what it might be in other terminology)