Function component_suffix_from_suffix 

pub fn component_suffix_from_suffix(
    field_name: &str,
    suffix: &str,
) -> Option<String>

Derive a generated helper suffix from a field name and shape suffix source.

Both inputs are normalized to snake_case. If the suffix is the same as the field name, this returns None so callers can use their own fallback. If the suffix repeats the field name as a prefix, the duplicate prefix is removed: ("email", "email_input") becomes Some("input").