Leave a single newline if reducing trailing. (#882)

While removing trailing newlines is a good idea, it is a problem when
editing C files which "must" have an empty line at the bottom.

So we leave just a single newline, if there were any.

Co-authored-by: Spenser Truex <truex@equwal.com>

.config/nvim/init.vim

@@ -113,7 +113,8 @@ set noshowcmd
 
 " Automatically deletes all trailing whitespace and newlines at end of file on save.
 	autocmd BufWritePre * %s/\s\+$//e
-	autocmd BufWritePre * %s/\n\+\%$//e
+    autocmd BufWritePre * %s/\n\+\%$//e
+    autocmd BufWritePre *.[ch] %s/\%$/\r/e
 
 " When shortcut files are updated, renew bash and ranger configs with new material:
 	autocmd BufWritePost bm-files,bm-dirs !shortcuts