Add goland's bluish tint color for user defined types

[soypat]

In Go, types are defined like so:

type logLevel int

Your extension colors these a bluish tint, which is similar to how Goland darcula does it.

It'd be great to extend this coloring for any time user defined types appear, such as:

package main

type logLevel int

const (
    Info logLevel = 0 // `logLevel` should be of different color than `Info`
    Warn logLevel = 1
    Error logLevel = 2
)
// same goes for functions argument types and return types
func SetLogLevel(lvl logLevel) logLevel {
   var packageLevel logLevel = lvl // and var declarations types
   var lotsLevels []logLevel
}

All logLevel appearances should have a slightly different color. See this image https://www.jetbrains.com/go/img/screenshots/1_Code_insight_2.png and this one https://www.jetbrains.com/go/img/screenshots/2_Navigation_Search.png

[soypat]

It is being taken care of by gopls!