Documentation issue: Depsets This page content belongs in a different place

Documentation URL: https://docs.bazel.build/versions/master/skylark/depsets.html

There are two problems.
1. This page has vital information about using the API. Specifically, how to construct a depset. It belong in the page where the API is described. https://docs.bazel.build/versions/master/skylark/lib/depset.html

2. Neither of the pages belong under .../skylark/. Depsets are not a Starlark feature, they are Bazel specific. It belongs in a "rule writing" section, which is not present in the current sidebar navigation.

Start by comparing the depsets page at https://docs.bazel.build/versions/master/skylark/depsets.html with the API page at https://docs.bazel.build/versions/master/skylark/lib/depset.html, then inspect the current sidebar navigation. Done means the construction guidance is placed with the API and both pages are organized under an appropriate Bazel rule-writing section rather than the Starlark section.

Written by the indexing model from the issue text.