patch 8.2.3830: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/buffer.c b/src/buffer.c
index be946d4..cbb57ef 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2385,7 +2385,7 @@
 	if ((options & GETF_ALT) && n == 0)
 	    emsg(_(e_no_alternate_file));
 	else
-	    semsg(_("E92: Buffer %d not found"), n);
+	    semsg(_(e_buffer_nr_not_found), n);
 	return FAIL;
     }
 
@@ -2669,9 +2669,9 @@
     }
 
     if (match == -2)
-	semsg(_("E93: More than one match for %s"), pattern);
+	semsg(_(e_more_than_one_match_for_str), pattern);
     else if (match < 0)
-	semsg(_("E94: No matching buffer for %s"), pattern);
+	semsg(_(e_no_matching_buffer_for_str), pattern);
     return match;
 }
 
@@ -3373,7 +3373,7 @@
 	    if (obuf->b_ml.ml_mfp != NULL || in_use)
 	    {
 		if (message)
-		    emsg(_("E95: Buffer with this name already exists"));
+		    emsg(_(e_buffer_with_this_name_already_exists));
 		vim_free(ffname);
 		return FAIL;
 	    }