patch 8.2.4003: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/typval.c b/src/typval.c
index fa0574d..be3a7b8 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -221,7 +221,7 @@
 		if (varp->v_type == VAR_BOOL)
 		    emsg(_(e_using_bool_as_number));
 		else
-		    emsg(_("E611: Using a Special as a Number"));
+		    emsg(_(e_using_special_as_number));
 		break;
 	    }
 	    return varp->vval.v_number == VVAL_TRUE ? 1 : 0;