================================================================================
String values
================================================================================

key = "quoted string"
key = ""

key = 'single quoted string'
key = ''

--------------------------------------------------------------------------------

(document
 (assignment
  (identifier)
  (string_interpolation
   (string_content)))
 (assignment
  (identifier)
  (string_interpolation
   (string_content)))
 (assignment
  (identifier)
  (string
   (string_content)))
 (assignment
  (identifier)
  (string
   (string_content))))