Add Autocomplete feature and more

[nonunknown]

I have a job where one of the requirements is able to do a kind of scripting lang to interact with the server, since I've found this awesome project, I'm improving it a lot from now on, to get similiar as possible with the editor inside godot! (and more features)

Feel free to merge with yours!

• Its in experimental stage (already working, but need to add more)

Also I would appreciate some review!