chore: update instructions

Author: sinedied

.github/instructions/genaiscript.instructions.md

@@ -11,9 +11,9 @@ GenAIScript is a custom runtime for node.js. It provides a set of unique APIs an
 
 ## Guidance for Code Generation
 
-- you always generate TypeScript code using ESM modules for Node.JS.
+- you always generate JavaScript code using ESM modules for Node.JS.
 - you prefer using APIs from GenAIScript `genaiscript.d.ts` rather than node.js. Do NOT use node.js imports.
 - you keep the code simple, avoid exception handlers or error checking.
 - you add `TODOs` where you are unsure so that the user can review them
 - you use the global types in genaiscript.d.ts are already loaded in the global context, no need to import them.
-- save generated code in the `./genaisrc` folder with `.genai.mts` extension
+- save generated code with `.genai.js` extension