Custom Tab completions for the bash shell. This depends on the
bash-completion package. Consult the documentation for that for how to
enable this.

Example for how to enable it for a single user in Debian GNU/Linux:

If your ~/.bashrc was automatically generated, it probably contains
something like this:

    # enable programmable completion features (you don't need to enable
    # this, if it's already enabled in /etc/bash.bashrc and /etc/profiles
    # sources /etc/bash.bashrc).
    # if [ -f /etc/bash_completion ]; then
    #     . /etc/bash_completion
    # fi

Uncomment the last three lines. This will enable the custom tab completions
for everything included in the bash-completion package.

Create ~/.local/share/bash-completions/completions if you don't
already have it, and copy the tab completion script (scummvm) to it.
Any newly started Bash shell should now have custom completions for
ScummVM. You can also run "source ~/.bashrc" to update your current
shell process.