patch 8.2.3453: autocmd not executed when editing a directory

Problem:    Autocmd not executed when editing a directory ending in a path
            separator inside try block.
Solution:   Return NOTDONE instead of FAIL. (closes #8885)

Author: brammool

src/fileio.c

@@ -338,7 +338,7 @@ readfile(
 	    filemess(curbuf, fname, (char_u *)_(msg_is_a_directory), 0);
 	    msg_end();
 	    msg_scroll = msg_save;
-	    return FAIL;
+	    return NOTDONE;
 	}
     }
 

src/testdir/test_autocmd.vim

@@ -2346,6 +2346,19 @@ func Test_throw_in_BufWritePre()
   au! throwing
 endfunc
 
+func Test_autocmd_in_try_block()
+  call mkdir('Xdir')
+  au BufEnter * let g:fname = expand('%')
+  try
+    edit Xdir/
+  endtry
+  call assert_match('Xdir', g:fname)
+
+  unlet g:fname
+  au! BufEnter
+  call delete('Xdir', 'rf')
+endfunc
+
 func Test_autocmd_SafeState()
   CheckRunVimInTerminal
 

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3453,
 /**/
     3452,
 /**/