I found out why the default editor does not show any popup menu options for our Sourcegraph window. Instead of the default EditorPopupMenu, the group created for the editor that we create is called BasicEditorPopupMenu which by default does not have any items added.
we can not reuse our existing implementation since that relies on the file being open inside the IDE to get the context. However, we do have more context available here since we have access to the PreviewContent so I've added the remaining bit (commit SHA) and build a blob URI instead of using the editor endpoint.
