make completion result more informative

[saks]

Currently when looking at completion result, it's hard to understand, what is the type value of particular key:

[3] ngx(content)> ngx.loca        
ngx.localtime  ngx.location

where

• ngx.localtime is a function
• ngx.location is a table

Make it more information so it will be easy to make a difference between:

• table
• function
• userdata
• cdata (?)
• the rest of lua types