lua `:` methods are not recognized

In lua, methods definitions using colon are not recognized.

compare

```lua
local MyClass = {}
function MyClass:new(obj)
    -- <cursor>
end
```
gps: ` `

```lua
local MyClass = {}
function MyClass.new(self, obj)
     -- <cursor>
end
```
gps: ` MyClass >  new`
