Add doc markdown files for sentry project settings API

doc/api/api_resources.md

@@ -29,6 +29,7 @@ The following API resources are available in the project context:
 | [Deployments](deployments.md)                                       | `/projects/:id/deployments`                                                                                                                                                                           |
 | [Discussions](discussions.md) (threaded comments)                   | `/projects/:id/issues/.../discussions`, `/projects/:id/snippets/.../discussions`, `/projects/:id/merge_requests/.../discussions`, `/projects/:id/commits/.../discussions` (also available for groups) |
 | [Environments](environments.md)                                     | `/projects/:id/environments`                                                                                                                                                                          |
+| [Error Tracking](sentry_project_settings.md)                        | `/projects/:id/error_tracking/sentry_project_settings`                                                                                                                                                |
 | [Events](events.md)                                                 | `/projects/:id/events` (also available for users and standalone)                                                                                                                                      |
 | [Issues](issues.md)                                                 | `/projects/:id/issues` (also available for groups and standalone)                                                                                                                                     |
 | [Issues Statistics](issues_statistics.md)                           | `/projects/:id/issues_statistics` (also available for groups and standalone)                                                                                                                          |

doc/api/sentry_project_settings.md

+# Sentry Project Settings API
+
+## Sentry Error Tracking Project Settings 
+
+The Sentry Project Settings API allows you to retrieve sentry error tracking settings for a project.
+
+### Retrieve Sentry Error Tracking Settings
+
+```
+GET /projects/:id/error_tracking/sentry_project_settings
+```
+
+| Attribute | Type    | Required | Description           |
+| --------- | ------- | -------- | --------------------- |
+| `id`      | integer | yes      | The ID of the project owned by the authenticated user |
+
+```bash
+curl --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/projects/1/error_tracking/sentry_project_settings
+```
+
+Example response:
+```json
+{
+  "project_name": "sample sentry project",
+  "sentry_external_url": "https://sentry.io/myawesomeproject/project"
+}
+```