Previously, users cannot enable boolean flags like `--show-all` in bat's
config since all options were expected to be either a string, or a list
of strings. With this commit boolean flags are simply appended to the
end of the config if they are set to `true`, and discarded otherwise.
For example, the config
{
theme = "TwoDark";
show-all = true;
lessopen = false;
}
would produce a config file that looks like
--theme='TwoDark'
--show-all
Fixes#4657
The way the `bat` module is currently written makes it essentially
impossible to use themes and syntaxes without IFD, since you must
provide the contents as string, instead of just giving a path to be
linked.
With this change, setting themes/syntaxes by-string will start issuing
warnings, and a new attribute model is added, lightly inspired by how
`programs.zsh.plugins` avoided this issue.
