win: getftype(symlink) returns 'link'

Vim doesn't detect symlinks correctly so stick with Neovim's behaviour.

runtime/doc/eval.txt

@@ -4208,8 +4208,7 @@ getftype({fname})					*getftype()*
 			getftype("/home")
 <		Note that a type such as "link" will only be returned on
 		systems that support it.  On some systems only "dir" and
-		"file" are returned.  On MS-Windows a symbolic link to a
-		directory returns "dir" instead of "link".
+		"file" are returned.
 
 							*getline()*
 getline({lnum} [, {end}])

src/nvim/testdir/test_stat.vim

@@ -86,7 +86,7 @@ func Test_win32_symlink_dir()
     let res = system('dir C:\Users /a')
     if match(res, '\C<SYMLINKD> *All Users') >= 0
       " Get the filetype of the symlink.
-      call assert_equal('dir', getftype('C:\Users\All Users'))
+      call assert_equal('link', getftype('C:\Users\All Users'))
     endif
   endif
 endfunc