Function to_gram_with_header 

pub fn to_gram_with_header(
    header: Record,
    patterns: &[Pattern<Subject>],
) -> Result<String, SerializeError>

Serializes patterns with a leading header record.

Emits the header as a top-level record followed by the patterns, joined by newlines.

Arguments

• header - Header record to serialize
• patterns - Patterns to serialize

Returns

• Ok(String) - Valid Gram notation with header