Remove orphan @ symbol from JSDoc in lookup.ts

The signal property's JSDoc comment contained an orphan '@' symbol on its
own line without a valid tag name. This is invalid JSDoc syntax.

This malformed tag was introduced in commit 2597d81 (2025-08-03) when
adding `@since` 1.8.0 annotation for AbortSignal.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: moreal

packages/webfinger/src/lookup.ts

@@ -57,7 +57,6 @@ export interface LookupWebFingerOptions {
   /**
    * AbortSignal for cancelling the request.
    * @since 1.8.0
-   * @
    */
   signal?: AbortSignal;
 }