YAML => KDL config update causes error when using backslash "\" as hotkey

[noyez]

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Basic information

zellij --version: zellij 0.32.0
stty size: 60 116
uname -av or ver(Windows): Darwin mbp16.local 21.6.0 Darwin Kernel Version 21.6.0: Sat Jun 18 17:07:22 PDT 2022; root:xnu-8020.140.41~1/RELEASE_ARM64_T6000 arm64

Further information
Reproduction steps, noticeable behavior, related issues, etc

Below is a sample of my yaml config:

keybinds:
    tmux:
        - action: [NewPane: Right, SwitchToMode: Normal,]
          key: [Char: '|',]
        - action: [NewPane: Right, SwitchToMode: Normal,]
          key: [Char: '\',]

This is the translated KDL config:

keybinds { 
    tmux {
        bind "|" { NewPane "Right"; SwitchToMode "normal"; }
        bind "\" { NewPane "Right"; SwitchToMode "normal"; }   // <--- this line causes the panic. 
    }
}

The bind line with a backslash causes a panic. A possible alternative is to use the raw string specifically for any hotkey with a backslack, namely:
bind r"\" { NewPane "Right"; SwitchToMode "normal"; }

[imsnif]

Fixed in #1879