Process variables defined with let or const

[OndrejSpanel]

Currently no autocomplete is offered for variables declared with let or const, they are ignored.

Adding support seams very easy, the tokens seem to be already parsed and processed fine.

Testing source:

function g() {
   let something_here = "123";
   var variableWithLongName;
   const anotherVariable;
   v
   anotherVariable;
}