declare module in index.d.ts should be declare namespace

`index.d.ts` line 8 uses `declare module looksSame` which causes the following error using the new `tsgo` TypeScript compiler.

`index.d.ts(8,16): error TS1540: A 'namespace' declaration should not be declared using the 'module' keyword. Please use the 'namespace' keyword instead.`

Fix:

```diff
-declare module looksSame {
+declare namespace looksSame {
```

See https://github.com/microsoft/TypeScript/pull/62876, https://github.com/microsoft/typescript-go/pull/2760, https://github.com/microsoft/typescript-go/issues/2873

Open index.d.ts and inspect line 8, where the looksSame declaration is defined. Check the declaration with the new tsgo TypeScript compiler and confirm that replacing the module declaration with a namespace declaration removes TS1540.

Written by the indexing model from the issue text.