patch 8.2.3983: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/fileio.c b/src/fileio.c
index 7c63a1a..01953d9 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4402,7 +4402,7 @@
 #if defined(FEAT_EVAL)
 		if (!aborting())
 #endif
-		    semsg(_("E321: Could not reload \"%s\""), buf->b_fname);
+		    semsg(_(e_could_not_reload_str), buf->b_fname);
 		if (savebuf != NULL && bufref_valid(&bufref) && buf == curbuf)
 		{
 		    // Put the text back from the save buffer.  First