Problem: Filetype detection fails if file name ends in many '~'.
Solution: Strip multiple '~' at the same time. (closesvim/vim#12553)
c12e4eecbb
In Nvim this already works as Lua filetype detection isn't subject to
such a small recursion limit as autocommands, but it still makes sense
to avoid unnecessary recursion.
Co-authored-by: Bram Moolenaar <Bram@vim.org>