Function full_print_fn_decl 

pub(crate) fn full_print_fn_decl(
    fn_decl: &FnDecl,
    header_len: usize,
    indent: usize,
    cx: &Context<'_>,
) -> impl Display

• header_len: The length of the function header and name. In other words, the number of characters in the function declaration up to but not including the parentheses. This is expected to go into a <pre>/code-header block, so indentation and newlines are preserved.
• indent: The number of spaces to indent each successive line with, if line-wrapping is necessary.