vimPlugins.himalaya-vim: fix source due to repo split (#195927)
Previously the Vim plugin was a part of the main repository, but the
author has elected to split out the project and move away from GitHub
to an open source Git forge @ https://git.sr.ht/~soywod/himalaya-vim/
As such, the previous plugin is currently broken, but now it can be
updated indepentently.
Co-authored-by: figsoda <figsoda@pm.me>
