Function section_header_present 

pub fn section_header_present(src: &str, name: &str) -> bool

Returns true when name is an active (non-commented) TOML section header in src.

Correctly handles:

• Exact bare header: [name] on its own line.
• Inline comment: [name] # remark — header is active.
• Implicit subtable parent: [name.foo] implies [name] is active.
• Commented header: # [name] — returns false.

Panics

Never panics in practice — regex::escape always produces a valid pattern.