Link issue to a Pull Request via the branch name

Our typical use of Jira and git (following the git-flow model) is to create a feature branch related to an issue in Jira and, when work is complete, request that branch to be pulled back to the develop branch. Typically, the individual commits on the feature branch do not reference a Jira key, so, the Pull Request will not reference any Jira issues.

We would like issue key to be included in the pull request summary along with any Jira issues referenced in commits related to the request.

For example, for issue JIRA-1234, we create branch feature/JIRA-1234 off develop and commit related changes:
abc1234 added feature
def2345 fixed bug

We then create a pull request:
feature/JIRA-1234 -> develop

In that pull request, we want the Jira issue to be referenced, in the details and/or in the Jira issue summary on the right.