`@ts-self-types` not detected if the file starts with a semicolon

`deno doc` is not picking up the `@ts-self-types` in https://jsr.io/@babel-test-6ae45912/core/0.0.5-8.0.0-alpha.15's `./lib/index.js`.

It seems like the problem is the semicolon in that file:
```ts
/* @ts-self-types="./index.d.ts" */
;
export const version = "7.26.8";
export { default as File } from "./transformation/file/file.js";
export { default as buildExternalHelpers } from "./tools/build-external-helpers.js";
```

If I remove it, it works.

I understand that it's weird to have a file starting with `;` (and tbh I'm not sure why my file has that 😅), but it's valid syntax and shouldn't affect the comment.

Reproduce the report with deno doc against the referenced ./lib/index.js, comparing the file with and without its leading semicolon. Trace the handling of the @ts-self-types comment and verify that the directive is detected when valid JavaScript begins with a semicolon; done means the reported JSR case works without removing that semicolon.

Written by the indexing model from the issue text.