Merge branch '299832-feature-flag-enable-individual-jira-issue-pages' into 'master'

Add documentation for Jira Issue Detail page

See merge request gitlab-org/gitlab!56182

changelogs/unreleased/299832-feature-flag-enable-individual-jira-issue-pages.yml

+---
+title: Enable :jira_issues_show_integration feature flag by default
+merge_request: 56182
+author:
+type: added

doc/user/project/integrations/jira.md

@@ -242,19 +242,38 @@ with a link to the commit that resolved the issue.
 
 > [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3622) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.2.
 
-You can browse and search issues from a selected Jira project directly in GitLab. This requires [configuration](#configure-gitlab) in GitLab by an administrator.
+You can browse, search, and view issues from a selected Jira project directly in GitLab,
+if your GitLab administrator [has configured it](#configure-gitlab):
 
-![Jira issues integration enabled](img/jira/open_jira_issues_list_v13.2.png)
+1. In the left navigation bar, go to **Jira > Issues list**.
+1. The issue list sorts by **Created date** by default, with the newest issues listed at the top:
 
-From the **Jira Issues** menu, click **Issues List**. The issue list defaults to sort by **Created date**, with the newest issues listed at the top. You can change this to **Last updated**.
+   ![Jira issues integration enabled](img/jira/open_jira_issues_list_v13.2.png)
 
-Issues are grouped into tabs based on their [Jira status](https://confluence.atlassian.com/adminjiraserver070/defining-status-field-values-749382903.html).
+1. To display the most recently updated issues first, click **Last updated**.
+1. In GitLab versions 13.10 and later, you can view [individual Jira issues](#view-a-jira-issue).
+
+Issues are grouped into tabs based on their [Jira status](https://confluence.atlassian.com/adminjiraserver070/defining-status-field-values-749382903.html):
 
 - The **Open** tab displays all issues with a Jira status in any category other than Done.
 - The **Closed** tab displays all issues with a Jira status categorized as Done.
 - The **All** tab displays all issues of any status.
 
-Click an issue title to open its original Jira issue page for full details.
+#### View a Jira issue
+
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/299832) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.10.
+> - It's [deployed behind a feature flag](../../feature_flags.md), disabled by default.
+> - It's enabled on GitLab.com.
+> - It's recommended for production use.
+> - For GitLab self-managed instances, GitLab administrators can opt to [enable it](#enable-or-disable-jira-issue-detail-view). **(PREMIUM)**
+
+WARNING:
+This feature might not be available to you. Check the **version history** note above for details.
+
+When viewing the [Jira issues list](#view-jira-issues), select an issue from the
+list to open it in GitLab:
+
+![Jira issue detail view](img/jira/jira_issue_detail_view_v13.10.png)
 
 #### Search and filter the issues list
 
@@ -304,3 +323,22 @@ which may lead to a `401 unauthorized` error when testing your Jira integration.
 If CAPTCHA has been triggered, you can't use Jira's REST API to
 authenticate with the Jira site. You need to log in to your Jira instance
 and complete the CAPTCHA.
+
+## Enable or disable Jira issue detail view
+
+Jira issue detail view is under development but ready for production use. It is
+deployed behind a feature flag that is **disabled by default**.
+[GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
+can enable it.
+
+To enable it:
+
+```ruby
+Feature.enable(:jira_issues_show_integration)
+```
+
+To disable it:
+
+```ruby
+Feature.disable(:jira_issues_show_integration)
+```