"""Merge short sentences in a list by concatenating them with the following sentence.

This function processes a list of sentences and merges any sentence with a length of 2 or fewer characters
with the subsequent sentence. The merging is done in-place, and the final list is adjusted to ensure no
short sentences remain at the end.

Args:
    sens (List[str]): A list of input sentences to be processed.

Returns:
    List[str]: A list of output sentences with short sentences merged appropriately.

Note:
    - If the last sentence in the list is short, it is merged with the second-to-last sentence.
    - The function handles edge cases where the list is empty or contains only one sentence gracefully.
"""