feat(doc): support JSDoc @event, @fires, @emits, @listens

[divybot]

Summary

Adds support for the JSDoc event-documentation tags so that classes which fire events (e.g. EventTarget subclasses) can be documented with deno doc and on JSR:

• @event <name> — declares an event a class can emit
• @fires <name> (alias @emits <name>) — documents which events a method or function fires
• @listens <name> — documents which events a symbol listens for

Names follow the JSDoc convention (e.g. Hurl#snowball, module:hurler~snowball) and an optional trailing description is captured.

The new tags are surfaced both in the terminal output of deno doc and in deno doc --json (under the new event / fires / listens tag kinds), making the metadata available to JSR's doc renderer.

Example

/**
 * A connection that fires events when its state changes.
 *
 * @event open - Fired when the connection opens.
 * @event close - Fired when the connection closes.
 */
export class Conn extends EventTarget {
  /**
   * Open the connection.
   *
   * @fires Conn#open
   */
  open(): void {}
}

class Conn extends EventTarget
  A connection that fires events when its state changes.

  @event open
      Fired when the connection opens.

  @event close
      Fired when the connection closes.

  open(): void
    Open the connection.

    @fires Conn#open

Implementation

The actual JSDoc-tag parsing lives in deno_doc. The matching change is proposed there as denoland/deno_doc#800 and is consumed here via a temporary [patch.crates-io] so the new spec test can verify end-to-end behaviour. Once the upstream PR is merged and released, the patch should be dropped and deno_doc bumped in Cargo.toml.

Upstream: denoland/deno_doc#800

Test plan

• New spec test tests/specs/doc/jsdoc_event/ exercises terminal output and --json output for @event, @fires, and @listens on a class.
• Upstream deno_doc PR adds unit tests for parsing and serialization of each new tag.

Refs #26697
Closes denoland/divybot#402