Update mod.ts file to export etc

[quentinadam]

I am suggesting the following minor changes :

• Export etc in mod.ts.
• Use the export { ... } from '...' syntax instead of import {...} from '...'; export { ... }

[paulmillr]

is mod.ts even needed? People can just use index.ts

[quentinadam]

It’s obviously not strictly needed but somewhat more conventional on Deno.

[paulmillr]

I don't remember why I did not do export in the first phase. It was probably related to types or something like that.

[paulmillr]

so we can merge this, but only the etc part; export needs to be reverted

[quentinadam]

I have reverted the export part.