fix scanner and keyword

[aspeddro]

Close #228

The end of and keyword must have a space

(source_file [0, 0] - [4, 0]
  (let_declaration [0, 0] - [0, 20]
    (let_binding [0, 4] - [0, 20]
      pattern: (value_identifier [0, 4] - [0, 8])
      body: (array [0, 11] - [0, 20]
        (number [0, 12] - [0, 13])
        (number [0, 15] - [0, 16])
        (number [0, 18] - [0, 19]))))
  (expression_statement [2, 0] - [2, 15]
    (pipe_expression [2, 0] - [2, 15]
      (subscript_expression [2, 0] - [2, 7]
        object: (value_identifier [2, 0] - [2, 4])
        index: (number [2, 5] - [2, 6]))
      (value_identifier_path [2, 9] - [2, 15]
        (module_identifier [2, 9] - [2, 11])
        (value_identifier [2, 12] - [2, 15]))))
  (expression_statement [3, 0] - [3, 15]
    (pipe_expression [3, 0] - [3, 15]
      (subscript_expression [3, 0] - [3, 7]
        object: (value_identifier [3, 0] - [3, 4])
        index: (number [3, 5] - [3, 6]))
      (value_identifier_path [3, 9] - [3, 15]
        (module_identifier [3, 9] - [3, 11])
        (value_identifier [3, 12] - [3, 15])))))