docs: public ExcelWriter addHeaderAlias(String name, String alias) {
  		Map<String, String> headerAlias = this.headerAlias;
  		if (null == headerAlias) {
  			headerAlias = new LinkedHashMap<>();
  		}
  		this.headerAlias = headerAlias;
  		headerAlias.put(name, alias);
  		return this;
  	}