Link to official Go caching docs

Instead of having a duplicate definitions to how to cache go modules,
link to the official caching documentations inside of the `ci/caching`
page.

The Go chacing documentation was introduced in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/27192

doc/development/go_guide/index.md

@@ -130,23 +130,8 @@ projects, and makes merge requests easier to review.
 In some cases, such as building a Go project for it to act as a dependency of a
 CI run for another project, removing the `vendor/` directory means the code must
 be downloaded repeatedly, which can lead to intermittent problems due to rate
-limiting or network failures. In these circumstances, you should cache the
-downloaded code between runs with a `.gitlab-ci.yml` snippet like this:
-
-```yaml
-.go-cache:
-  variables:
-    GOPATH: $CI_PROJECT_DIR/.go
-  before_script:
-    - mkdir -p .go
-  cache:
-    paths:
-      - .go/pkg/mod/
-
-test:
-  extends: .go-cache
-  # ...
-```
+limiting or network failures. In these circumstances, you should [cache the
+downloaded code between](../../ci/caching/index.md#caching-go-dependencies).
 
 There was a [bug on modules
 checksums](https://github.com/golang/go/issues/29278) in Go < v1.11.4, so make