[docs][easy] Some graphql beta cleanup (MystenLabs#16136)

## Description 

Describe the changes or additions included in this PR.

## Test Plan 

How did you test the new or updated feature?

---
If your changes are not user-facing and do not break anything, you can
skip the following section. Otherwise, please briefly describe what has
changed under the Release Notes section.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

docs/content/references/sui-api.mdx

@@ -4,7 +4,7 @@ title: Sui API
 
 :::info
 
-The Sui API is upgrading to use GraphQL soon. See [GraphQL RPC Beta](./sui-api/beta-graph-ql.mdx) for details.
+The Sui API is upgrading to GraphQL. See [Sui GraphQL RPC](../concepts/graphql-rpc.mdx) for more information.
 
 :::