Function rustfmt_nightly::items::rewrite_fn_base

fn rewrite_fn_base(
    context: &RewriteContext<'_>, 
    indent: Indent, 
    ident: Ident, 
    fn_sig: &FnSig<'_>, 
    span: Span, 
    fn_brace_style: FnBraceStyle
) -> Option<(String, bool, bool)>