Fix code scanning alert - Disallow unused variables

[tolauwae]

Tracking issue for:

• https://github.com/TOPLLab/latch/security/code-scanning/283

latch/src/sourcemap/SourceMapper.ts

Lines 110 to 114 in 4ac3d78

	for (const text in matches) {
	const index: number = +find(/func\[([0-9]+)/, line.toString());
	const local: string = find(/<(.*)>/, line.toString());
	locals.push({index: index, name: local, type: 'undefined', mutable: true, value: ''});
	}