Allow option `sourcemaps: "hidden"`

No matter what sourcemap option you choose with `tsup` the bundle will end up including sourcemaps comments.
Any plans in support the "hidden" option for sourcemaps?
Should sourcemaps: `false` avoid including the sourcemaps comments? :>

e.g. rollup allows this:
https://rollupjs.org/configuration-options/#output-sourcemap

Start by tracing how tsup handles its sourcemap option and compare the requested behavior with Rollup's output.sourcemap documentation. Done means supporting the hidden option and confirming whether false suppresses sourcemap comments, with coverage for the relevant option values.

Written by the indexing model from the issue text.