xC: general.save_on_quit -> general.autosave

Power outages and similar situations make the former unreliable,
so get rid of any false promise it might seem to give.

xC.c

@@ -2422,8 +2422,8 @@ static struct config_schema g_config_server[] =
 
 static struct config_schema g_config_general[] =
 {
-	{ .name      = "save_on_quit",
-	  .comment   = "Save configuration before quitting",
+	{ .name      = "autosave",
+	  .comment   = "Save configuration automatically after each change",
 	  .type      = CONFIG_ITEM_BOOLEAN,
 	  .default_  = "on" },
 	{ .name      = "debug_mode",
@@ -11363,6 +11363,8 @@ static bool
 handle_command_set_assign
 	(struct app_context *ctx, struct strv *all, char *arguments)
 {
+	hard_assert (all->len > 0);
+
 	char *op = cut_word (&arguments);
 	bool add = false;
 	bool remove = false;
@@ -11397,6 +11399,9 @@ handle_command_set_assign
 		free (key);
 	}
 	config_item_destroy (new_);
+
+	if (get_config_boolean (ctx->config.root, "general.autosave"))
+		save_configuration (ctx);
 	return true;
 }
 
@@ -14748,9 +14753,6 @@ main (int argc, char *argv[])
 
 	CALL (ctx.input, stop);
 
-	if (get_config_boolean (ctx.config.root, "general.save_on_quit"))
-		save_configuration (&ctx);
-
 	app_context_free (&ctx);
 	toggle_bracketed_paste (false);
 	free_terminal ();