Minor: I wish `wush` was easier to install with Go

Currently, I get

```console
$ go install github.com/coder/wush@latest
go: downloading github.com/coder/wush v0.3.0
go: github.com/coder/wush@latest: module github.com/coder/wush@latest found (v0.3.0), but does not contain package github.com/coder/wush
```

The best way I have found to substitute for this is a bit awkward:

```shell
git clone https://github.com/coder/wush@latest
cd wush/cmd/wush
go install .
```

I'm not familiar enough with Go packages to know whether there's a better way of whether this is easy or impossible to fix.