Function indent_columns_for_new_line 

pub fn indent_columns_for_new_line(
    method: IndentMethod,
    prev: Option<&str>,
    next: Option<&str>,
    unit: IndentUnit,
    brackets: BracketSyntax,
) -> u16

indent_for_new_line in display columns, before rendering. Separate so IN.2’s engine can compare its own answer against the fallback’s without allocating.