Function print_as_escaped 

pub fn print_as_escaped(
    codepoint: TCodepoint,
    additional_escape_map: &HashMap<TCodepoint, String>,
) -> String

Render a single codepoint as a printable, escaped string.

additional_escape_map is checked first (e.g. {'-': "\\-"}), then the C-escape table, then a printable-ASCII passthrough for 0x20..=0x7E; anything else becomes a \xHH / \uHHHH / \UHHHHHHHH hex escape sized by magnitude. Faithful to C++ EscapeString.