message: Update k-th-smallest-prime-fraction.py
diff: # Time: O(nlogr)
  # Space: O(1)
  +# Another cool O(n) solution by using quick select with median of median could be found here:
  +# https://leetcode.com/problems/k-th-smallest-prime-fraction/discuss/115545/O(n)
  +
  # A sorted list A contains 1, plus some number of primes.
  # Then, for every p < q in the list, we consider the fraction p/q.
  #
  