Add GraphQL removed items docs

- add links and template

doc/api/graphql/index.md

@@ -82,6 +82,10 @@ The process is as follows:
    release post (at or prior to X.11 and X.5 releases).
 1. Fields meeting criteria are removed in X.0 or X.6.
+### List of removed items
+
+View the [fields, enums, and other items we removed](removed_items.md) from the GraphQL API.
+
 ## Available queries
 The GraphQL API includes the following queries at the root level:

doc/api/graphql/reference/index.md

@@ -15,6 +15,8 @@ fields and methods on a model are available via GraphQL.
 CAUTION: **Caution:**
 Fields that are deprecated are marked with **{warning-solid}**.
+Items (fields, enums, etc) that have been removed according to our [deprecation process](../index.md#deprecation-process) can be found
+in [Removed Items](../removed_items.md).
 ## Object types

doc/api/graphql/removed_items.md

+# GraphQL API removed items
+
+GraphQL is a versionless API, unlike the REST API.
+Occasionally, items have to be updated or removed from the GraphQL API.
+According to our [process for removing items](index.md#deprecation-process), here are the items that have been removed.
+
+## GitLab 13.6
+
+Fields removed in [GitLab 13.6](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/44866):
+
+| Field name           | GraphQL type             | Deprecated in | Use instead                |
+| -------------------- | --------------------     | ------------- | -------------------------- |
+| `date`               | `Timelog` **(STARTER)**  | 12.10         | `spentAt`                  |
+| `designs`            | `Issue`, `EpicIssue`     | 12.2          | `designCollection`         |
+| `latestPipeline`     | `Commit`                 | 12.5          | `pipelines`                |
+| `mergeCommitMessage` | `MergeRequest`           | 11.8          | `latestMergeCommitMessage` |
+| `token`              | `GrafanaIntegration`     | 12.7          | None. Plaintext tokens no longer supported for security reasons. |

lib/gitlab/graphql/docs/templates/default.md.haml

@@ -14,6 +14,8 @@
   CAUTION: **Caution:**
   Fields that are deprecated are marked with **{warning-solid}**.
+  Items (fields, enums, etc) that have been removed according to our [deprecation process](../index.md#deprecation-process) can be found
+  in [Removed Items](../removed_items.md).
 \
 :plain