Refactor file structure and modify index.js

This commit includes renaming of two source files for better clarity and modifications to index.js. The file 'text.js' has been renamed to 'custom.js' and 'javascript.js' has been renamed to 'lua.js' to better reflect their functionalities and due to an error. Additionally, 'index.js' has been updated to accommodate these changes.

Author: Sarxzer

src/blocks/text.js renamed to src/blocks/custom.js

@@ -1,6 +1,6 @@
 import * as Blockly from "blockly";
-import { blocks } from "./blocks/text";
-import { forBlock } from "./generators/javascript";
+import { blocks } from "./blocks/custom";
+import { forBlock } from "./generators/lua";
 import { luaGenerator } from "blockly/lua";
 import { save, load } from "./serialization";
 import { toolbox } from "./toolbox";