alsinmr/SLEEPY: Tumbling correction

SLEEPY 1.1.1 is a minor update to version 1.1.0: We correct the "tumbling" function in sl.Tools. The tumbling function evaluates proximity of orientations in a powder average by taking the sum of squared arc lengths of vectors starting on the x,y, and z axes between pairs of orientations. This value is used to scale the rate of exchange between orientations (see eq. 17 in paper, https://doi.org/10.1038/s41467-025-65091-6). In version 1.1.0 (and prior versions), the arc length between the x and y vectors was inadvertently set to zero (Thanks to Wanli Zhang for the bug report). This should not impact simulations where alpha tumbling is not included, but may otherwise induce minor changes. If you observe major changes in a simulation, I would be happy if it could be reported (albert.smith-penzel@uni-leipzig.de)