#1872 Remove extra carriage returns when fixing files on Windows

autoload/ale/util.vim

@@ -405,7 +405,7 @@ endfunction
 " the buffer.
 function! ale#util#Writefile(buffer, lines, filename) abort
     let l:corrected_lines = getbufvar(a:buffer, '&fileformat') is# 'dos'
-    \   ? map(copy(a:lines), 'v:val . "\r"')
+    \   ? map(copy(a:lines), 'substitute(v:val, ''\r*$'', ''\r'', '''')')
     \   : a:lines
 
     call writefile(l:corrected_lines, a:filename) " no-custom-checks