Quick fix to add missing pattern matching

Suggestion to code editor quick fixes:

![example](http://i.imgur.com/RiMrnJkg.png)

When matching over enum or discriminated union type, and gotten warning "Incomplete pattern matches", provide a quick hint fix possibility to add missing enums.
