Add reference link to Trie documentation in docstring

Author: Hemanthkumar2k04

data_structures/trie/trie.py

@@ -4,6 +4,8 @@
 A Trie is a tree-like data structure that stores strings efficiently. Each node represents
 a character, and paths from root to leaf nodes form complete words.
 
+Reference: https://en.wikipedia.org/wiki/Trie
+
 Time Complexity:
   - Insert: O(m) where m is the length of the word
   - Search: O(m) where m is the length of the word