I have a definition like this:

static HELP: &str = concat! {
    indoc! { "
        Prints help.

        Usage: " }, env!("CARGO_BIN_NAME"), indoc! { " [options]

        Options:
            -h, --help
    " },
};

formatdoc! {} can't be used because of the following error:

cannot call non-const fn `std::fmt::format` in statics
calls in statics are limited to constant functions, tuple structs and tuple variants

I'm not sure though how the macro would determine what parts to apply the rules on that are described in README.md.