patch 8.2.0888: readdirex() returns size -2 for a directory

Problem:    Readdirex() returns size -2 for a directory.
Solution:   Add missing "else". (Ken Takata, closes #6185)

src/fileio.c

@@ -4575,7 +4575,7 @@ create_readdirex_item(char_u *path, char_u *name)
 	if (S_ISDIR(st.st_mode))
 	    size = 0;
 	// non-perfect check for overflow
-	if ((off_T)size != (off_T)st.st_size)
+	else if ((off_T)size != (off_T)st.st_size)
 	    size = -2;
 	if (dict_add_number(item, "size", size) == FAIL)
 	    goto theend;

src/testdir/test_functions.vim

@@ -1864,13 +1864,15 @@ endfunc
 
 func Test_readdirex()
   call mkdir('Xdir')
-  call writefile([], 'Xdir/foo.txt')
-  call writefile([], 'Xdir/bar.txt')
+  call writefile(['foo'], 'Xdir/foo.txt')
+  call writefile(['barbar'], 'Xdir/bar.txt')
   call mkdir('Xdir/dir')
 
   " All results
   let files = readdirex('Xdir')->map({-> v:val.name})
   call assert_equal(['bar.txt', 'dir', 'foo.txt'], sort(files))
+  let sizes = readdirex('Xdir')->map({-> v:val.size})
+  call assert_equal([0, 4, 7], sort(sizes))
 
   " Only results containing "f"
   let files = 'Xdir'->readdirex({ e -> stridx(e.name, 'f') != -1 })

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    888,
 /**/
     887,
 /**/