input: Write a python function to find the word with the highest score in a given text, where the score of each word is calculated by summing the positions of its letters in the alphabet (a=1, b=2, ..., z=26).
  assert highest_scoring_word("The cat runs fast") == "runs"
  assert highest_scoring_word("hello world") == "world"
  assert highest_scoring_word("a quick brown fox jumps over the lazy dog") == "quick"
output: def highest_scoring_word(text):
      def word_score(word):
          return sum(ord(char) - ord('a') + 1 for char in word.lower() if 'a' <= char <= 'z')
  
      words = text.split()
      highest_word = max(words, key=word_score)
      return highest_word