iterate over all ILuaTypeInfer extensions

[knoxfighter]

This is a quick fix/workaround for #110

I decided against trying to implement the unknown type. I don't have enough experience with your code to do such a overhaul :(

This will allow me to run my detection code before your's is run and if i don't find anything, i can just return null to make the original guessing do it's work.

If you change the design of this extension, i will just change my code for it. It seems like i am the only person that has EmmyLua or Luanalysis as dependency. https://plugins.jetbrains.com/plugins/list/?build=IC-212.*