Sometimes we also used `Number` and `integer`, but `number` is what
the JSDoc documentation recommends.

Sometimes we also used `String`, but `string` is the what the JSDoc
documentation recommends.

…ments

Square brackets are recommended to indicate optional parameters. Using
them helps for automatically generating correct documentation.

Sometimes we also used `@return` or `@returns`, but `@type` is what
the JSDoc documentation recommends. This also improves the documentation
because before this commit the types were not shown and now they are.

Sometimes we also used `@return`, but `@returns` is what the JSDoc
documentation recommends. Even though `@return` works as an alias, it's
good to use the recommended syntax and to be consistent within the
project.

…rker`

Both classes live inside a closure with the same name, which confuses
JSDoc. Move the documentation to the inner class to deduplicate them.

…tion

This file only contains helper functions and should not be listed in the
documentation since they are not part of the public API.

This commit allows JSDoc to generate all API documentation in the
`pdfjsLib` module (namespace) so the documentation becomes easier to
navigate.