Comment about "6.6 is wrong"

[nhenriksen]

https://github.com/slochower/pAPRika/blob/a440085f6197be360e38f810bfe19bdde42e5094/test/test_restraints.py#L326

I think the problem is the following:

1. The attachment was supposed to go in fraction increments of 0.25, while the release was to go in increments of 0.33.
2. However, due to rounding/precision issues, this meant that it didn't quite get the final value correct (4.96 instead of 5.0), so it made another window (6.6) which is wrong.
3. I left the bugginess alone, since it was low priority

For fraction increments, I think we need to figure out (math) how many windows we need, and when the result is non-integer, then we need to round, and adjust the increments appropriately. As an easy step forward, we could just adjust the final window to the correct value, rather than figuring out how to adjust all of them.