patch 8.2.4012: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move the last error messages to errors.h.
diff --git a/src/if_mzsch.c b/src/if_mzsch.c
index 09dd3de..c24edf3 100644
--- a/src/if_mzsch.c
+++ b/src/if_mzsch.c
@@ -1248,7 +1248,7 @@
 #endif
 	if (load_base_module_failed || startup_mzscheme())
 	{
-	    emsg(_("E895: Sorry, this command is disabled, the MzScheme's racket/base module could not be loaded."));
+	    emsg(_(e_sorry_this_command_is_disabled_the_mzscheme_racket_base_module_could_not_be_loaded));
 	    return -1;
 	}
 	initialized = TRUE;