Problem: filetype: ed script files not recognised.
Solution: Add filetype detection for *.ed files and shebang lines,
include syntax script and syntax tests.
Features of the ed syntax file:
- BSD and GNU extensions are supported
- Andrew L. Moore's ed extensions are not supported
- Rebuild synmenu.vim
closes: vim/vim#19602https://github.com/vim/vim/commit/c28515b9992e52f49c3fd90484601c248c672aec
Co-authored-by: Doug Kearns <dougkearns@gmail.com>
