pub fn parse(content: &str) -> Result<Frontmatter, FrontmatterError>Expand description
Parses the leading --- frontmatter block. A file without a block parses
to an empty Frontmatter; a malformed block is an error so a typo never
silently registers a ticket under the wrong identity.
Reports only the first problem. Callers that want every problem at once
use parse_collecting.