Add comment explaining the logic behind the if statement

Author: mokeddembillel

convert_hf_to_gguf.py

@@ -527,6 +527,7 @@ def get_vocab_base(self) -> tuple[list[str], list[int], str]:
                 if token in added_vocab:
                     # We need to manually encode and decode the added tokens in case special characters
                     # used for `\n` / `\t` have been manually added in the added tokens
+                    # To avoid unexpected issues - we make sure to encode single-char tokens
                     if len(token) == 1:
                         token = tokenizer.decode(tokenizer.encode(token, add_special_tokens=False))