Yesterday version 1.3.17 of BashSupport Pro was released, https://plugins.jetbrains.com/plugin/13841-bashsupport-pro/update/87950. This update finallyy adds most of the missing pieces when used with the JetBrains Shell plugin. Go to declaration, find usages, rename, quick documentation, etc. are now available.
Compared with the old BashSupport plugin it’s faster, smarter, and more complete. For example, the support for sourced files is a lot better and even support shellcheck source directives to handle dynamic file paths.