patch 8.2.3967: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/fileio.c b/src/fileio.c
index 73c7243..1aeb483 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4809,7 +4809,7 @@
     if (!ok)
     {
 	failed = TRUE;
-	semsg(_(e_notopen), path);
+	semsg(_(e_cant_open_file_str), path);
     }
     else
     {
@@ -4879,7 +4879,7 @@
     if (dirp == NULL)
     {
 	failed = TRUE;
-	semsg(_(e_notopen), path);
+	semsg(_(e_cant_open_file_str), path);
     }
     else
     {