Add Go guidelines to developer docs

What does this MR do?

Adds our Go guidelines to the development doc.

Related issues

Closes #54494 (closed)

Author's checklist

• Apply the correct labels and milestone
• Crosslink the document from the higher-level index: added to doc/development/README.md
• Crosslink the document from other subject-related docs: added to doc/development/contributing/style_guides.md
• Feature moving tiers? Make sure the change is also reflected in features.yml
• Correctly apply the product badges and tiers
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9462

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker) (development guidelines)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards

/label ~Documentation golang development guidelines

doc/development/contributing/style_guides.md

@@ -21,6 +21,7 @@
    of _prohibited this user from being saved due to the following errors:_ the
    text should be _sorry, we could not create your account because:_
 1. Code should be written in [US English][us-english]
+1. [Go](../go_guide/index.md)
 
 This is also the style used by linting tools such as
 [RuboCop](https://github.com/bbatsov/rubocop) and [Hound CI](https://houndci.com).