merge_neighbors: Confusing default distance

[pcworld]

merge_neighbors by default has distance=1, which means that it will merge intervals that have gaps in between them.
This is not what I had intuitively expected after reading the README and skimming the function's documentation.
I would have expected that by default, it would only merge intervals that do not have any gap between them, i.e. that [0,1) and [2,3) would not be merged (but [0,1) and [1,3) would be).