Remove use of shebang

- Removed shebang line from generate and clear scripts
- Added `.js` extension to generate and clear script files
- Updated scripts in `package.json` accordingly

scripts/clear.js

@@ -1,4 +1,3 @@
-#!/usr/bin/env node
 const fs = require("fs");
 const path = require("path");
 

scripts/generate.js

@@ -1,4 +1,3 @@
-#!/usr/bin/env node
 const fs = require("fs");
 const path = require("path");
 const config = require("../ligma.config");