No icon for "moderate rain"

[krisgesling]

Describe the bug
Just noticed the home screen only had the temperature and no icon.
Asking for the weather reported "moderate rain" and also had no weather icon.

Expected behavior
Assuming we are just missing some of the less used

Environment (please complete the following information):

• Device type: Mark II
• Mycroft-core version: Latest

[NeonDaniel]

I noticed similar behavior but didn't grab the icon code out of logs at the time.. I added in codes from the documentation that appear to be missing in the skill (night codes associated with several conditions), but I'm not sure of a good way to test since I don't know what API returns to mock..