patch 8.2.3987: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/if_tcl.c b/src/if_tcl.c
index 65f25c1..75f904a 100644
--- a/src/if_tcl.c
+++ b/src/if_tcl.c
@@ -1710,7 +1710,7 @@
 #ifdef DYNAMIC_TCL
     if (!tcl_enabled(TRUE))
     {
-	emsg(_("E571: Sorry, this command is disabled: the Tcl library could not be loaded."));
+	emsg(_(e_sorry_this_command_is_disabled_tcl_library_could_not_be_loaded));
 	return FAIL;
     }
 #endif
@@ -1874,7 +1874,7 @@
     {
 	char buf[50];
 
-	sprintf(buf, _("E572: exit code %d"), tclinfo.exitvalue);
+	sprintf(buf, _(e_exit_code_nr), tclinfo.exitvalue);
 	tclerrmsg(buf);
 	if (tclinfo.exitvalue == 0)
 	{