patch 8.2.1832: readdirex() error is displayed as a message

Problem:    readdirex() error is displayed as a message. (Yegappan Lakshmanan)
Solution:   Use semsg() instead of smsg().
diff --git a/src/fileio.c b/src/fileio.c
index 83924b3..3d6ff0d 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4743,7 +4743,7 @@
     if (!ok)
     {
 	failed = TRUE;
-	smsg(_(e_notopen), path);
+	semsg(_(e_notopen), path);
     }
     else
     {
@@ -4813,7 +4813,7 @@
     if (dirp == NULL)
     {
 	failed = TRUE;
-	smsg(_(e_notopen), path);
+	semsg(_(e_notopen), path);
     }
     else
     {
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index b816125..e8c372c 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1959,6 +1959,8 @@
         \ ['bar.txt_file', 'dir_dir', 'foo.txt_file', 'link_link'])
   endif
   eval 'Xdir'->delete('rf')
+
+  call assert_fails('call readdirex("doesnotexist")', 'E484:')
 endfunc
 
 func Test_readdirex_sort()
diff --git a/src/version.c b/src/version.c
index b3cbf81..6368b5e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1832,
+/**/
     1831,
 /**/
     1830,