Clarification on Jira create branch limitations

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Per discussion in Slack on Aug 11, there's opportunity to clarify in the docs that the Create branch functionality within the Jira Development Panel is only supported in the GitLab for Jira App.

Latest comment from Andy on the Ecosystem Engineering team:

We’ve built the create branch feature for the Jira app. But officially the feature is only supported for Bitbucket. I found this in the Jira documentation: The Development panel is shown on the View Issue screen, and provides the following functionality: Bitbucket Cloud and Bitbucket Server: view and create branches, view commits, and view and create pull requests Fisheye / Crucible: view commits and branches, view and create reviews Bamboo: view the status of builds and deployments GitHub / GitLab: view commits, branches, and pull requests

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