Enforce JSDoc block comments

Right now, the compiler only looks at JSDoc comments for descriptions and annotations. [JSDoc ignores comments](https://jsdoc.app/about-getting-started) that don't start with `/**`, including `/***` with three stars. For example, all those comments are ignored, and the compiler currently uses rest-api-spec to fill them in: https://github.com/elastic/elasticsearch-specification/blob/e3d34e5af85ef01caa3f46cf4ef517a0216dcebb/specification/_global/search_mvt/SearchMvtRequest.ts#L138-L162 To fix this, I suggest we only accept two types of comments: 1. JSDoc-style comments starting with `/**`, and 2. `//` line comments when we don't want a given comment to be interpreted by the compiler.