Suggest completions only from imported libraries

**Is your feature request related to a problem? Please describe.**

I really like HLS, but it is frustrating and slow how it seems to suggest completions not only from currently imported libraries, but from any library possible. Even with a small amount of dependencies this makes the amount of suggested completions massive and at least for me makes VSCode run quite sluggish. It also somewhat often makes it so I can't find the function I'm looking for, since the exact same (or very similar) functions are exported from 10 different libraries.

**Describe the solution you'd like**
I'd like an option to have suggestions only show for libraries that are currently imported in the current file.