IDML fails when trying to parse multi-line string variables with logical operators

When you have a variable like:
```
let input1 = "HELLO
WORLD"
```
Works fine.

But when you have:
```
let input1 = "HELLO
AND WORLD"
```
It  throws the following error:
```
Couldn't compile test.idml: Line 5:0 no viable alternative at input 'WORLD'
```
