Also ran gofmt on everything. Thanks again @paralin. #334

Co-authored-by: Christian Stewart <christian@paral.in>

Thank you @icholy for identifying these in
https://github.com/nhooyr/websocket/pull/259#issuecomment-702279421

See https://github.com/nhooyr/websocket/issues/182

Closes #182

Closes #179

Too many improvements and changes to list.

Will include a detailed changelog for release.

Much faster.

Will make it much more convenient and less error prone to access
the StatusCode of a *CloseError.

Subprotocols didn't work with WASM at all before.

Should prevent the sporadic failures in CI.

Closes #121