Clarify Go client installation

### Type of issue

Inaccurate

### What documentation page is affected

https://www.elastic.co/docs/reference/elasticsearch/clients/go/installation

### What happened?

Mismatch of version numbers in text description and go.mod snippet:

---

# Installation [installation]

To install the 8.x version of the client, add the package to your `go.mod` file:

```text
require github.com/elastic/go-elasticsearch/v9 9.0
```

---

Also, after running `go get github.com/elastic/go-elasticsearch/v9` the line in the go.mod file is:

```
github.com/elastic/go-elasticsearch/v9 v9.0.0
```

I feel it more idiomatic if it said "to install the client run `go get ...` rather than display the line from go.mod??

### Additional info

_No response_