completions: do not render empty multi-line documentation (#7279)
Thorsten Ball
created
I ran into this a lot with Go code: the documentation would be empty so
we'd display a big box with nothing in it.
I think it's better if we only display the box if we have documentation.
Release Notes:
- Fixed documentation box in showing up when using auto-complete even if
documentation was empty.
## Before

## After
