Change citation in README and documentation when paper is printed #312

When the morph paper is printed, make sure we:

• Change the README and documentation so they tell the users to cite the following manuscript.

Yang, A., Farrow, C. L., Juhás, P., Iglesias, L. K., Liu, C.-H., Marks, S. D., Wall, V. R. K., Safin, J., Drewry, S. M., Myers, C., Hanlon, D. F., Leonard, N., Petrovic, C., Jeong, A., Talapin, D. V., Nazar, L. F., Zhou, H., Teitelbaum, S. W., van Driel, T. B., Banerjee, S., Bozin, E. S., Toney, M. F., Page, K., Ginsberg, N. S., and Billinge, S. J. L., diffpy.morph: Python tools for model independent comparisons between sets of 1D functions, Phys. Rev. Mater., <volume>, <pages>, (2026) (doi: 10.1103/t39r-v3lx)

We should also:

• Update the ArXiv paper to the newest version.
• Link the PRM doi to the ArXiv copy.