pub const ISSUE_REF_PATTERN: &str = "^[A-Za-z0-9-]+/[A-Za-z0-9._-]+#[1-9][0-9]{0,18}$";Expand description
The pattern every IssueRef is spelled in: owner/name#N, the number at most nineteen
digits — every such number fits the u64 it is read into.
What the JSON Schema publishes; IssueRef’s FromStr is the same rule written out, and
tests/issue_ref.rs derives a matcher from this constant and holds the two to one language.