functions: attributes generated by quick start are undocumented

**Describe the Issue:**

If you generate a quick start for `Go` with `doctl` ...

```bash
doctl serverless init --language go test
```

`doctl` will generate a quick start and it's `project.yml` for the language. If you inspect the generated `project.yml`

```yaml
parameters: {}
environment: {}
packages:
- name: sample
shared: false
environment: {}
parameters: {}
annotations: {}
functions:
- name: hello
binary: false
main: ""
runtime: go:default
web: true
webSecure: false
parameters: {}
environment: {}
annotations: {}
limits: {}
```

The `binary` and `annotations` attributes are undocumented at [Project Configuration YAML File](https://docs.digitalocean.com/products/functions/reference/project-configuration/)

**Environment:**
```
doctl version 1.105.0-release
release 1.106.0 is available, check it out!
```

Start with the Project Configuration YAML File documentation linked in the issue, then run `doctl serverless init --language go test` and inspect the generated `project.yml`. Document the `binary` and `annotations` attributes, and verify that both generated fields are covered in the configuration reference.

Written by the indexing model from the issue text.