Function compute_dbg_replacement 

fn compute_dbg_replacement(
    macro_expr: MacroExpr,
    make: &SyntaxFactory,
) -> Option<(Vec<NodeOrToken<SyntaxNode, SyntaxToken>>, Option<Expr>)>

Returns None when either

• macro call is not dbg!()
• any node inside dbg!() could not be parsed as an expression
• (macro_expr has no parent - is that possible?)

Returns Some(_, None) when the macro call should just be removed.