/**
 * Copies the casing of `source` onto `target`, from the start.
 * Only affects characters that exist in the same position in both strings.
 * Appends remaining part of `target` (if longer) in lowercase.
 *
 * @param source Original input word (with desired casing)
 * @param sourceLower Lowercase version of source
 * @param target Plural version (assumed lowercase)
 */
export declare function preserveCasing(source: string, sourceLower: string, target: string): string;