docs: add time and space complexity to selection_sort docstring

Added Time Complexity O(n^2) and Space Complexity O(1) documentation to the selection_sort function docstring, improving code documentation for beginners as requested in issue #13948.

Author: kl2400033266

sorts/selection_sort.py

@@ -5,6 +5,12 @@ def selection_sort(collection: list[int]) -> list[int]:
     :param collection: A list of integers to be sorted.
     :return: The sorted list.
 
+
+    Time Complexity: O(n^2) - Due to the nested loops, where n is the length
+        of the collection. The outer loop runs n-1 times, and the inner loop
+        runs n-i-1 times for each iteration.
+    Space Complexity: O(1) - Only a constant amount of extra space is used
+        for variables (length, i, min_index, k).
     Examples:
     >>> selection_sort([0, 5, 3, 2, 2])
     [0, 2, 2, 3, 5]