bzl_library targets not correct

[alexeagle]

in #82 I fixed it, but it already regressed.

in deps attribute of starlark_doc_extract rule @@rules_multitool~//multitool:multitool.doc_extract: missing bzl_library targets for Starlark module(s) @platforms//host:constraints.bzl.

This added load statement
https://github.com/theoremlp/rules_multitool/pull/80/files#diff-7d06750bf4c88daaf48ddc1873d0494fda10b1eb97a250aa2c14ef150606d813
wasn't accompanied by the deps update to the bzl_library.

I'll send a PR to fix and also prevent regressions.

[alexeagle]

FYI, my docgen pipeline showed the failure:
alexeagle/doc.bzl#47