patch 8.2.3961: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/gui_w32.c b/src/gui_w32.c
index 4edce2e..d5ffd16 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -1547,7 +1547,7 @@
     if (get_logfont(&lf, name, NULL, giveErrorIfMissing) == OK)
 	font = get_font_handle(&lf);
     if (font == NOFONT && giveErrorIfMissing)
-	semsg(_(e_font), name);
+	semsg(_(e_unknown_font_str), name);
     return font;
 }