Provide documentation for code completion recommendations
While writing code and code completion kicking in for a specific known (API-)command / variable etc. the extension could provide some information from the documentation about the recommended completion bit. This should help users decide which item from the code completion to select.
For custom procedures and variables the documentation could be determined based on the comments provided ... before it? after it? there's no fixed way on how to document custom procedures etc. ala JavaDoc, but we could invent something for that. (e.g. using ## for comments or starting a multi-line comment with (** and ending with **) to provide that kind of documentation before the variable / procedure without an empty line in between).