Complete PR without Merged by jocmet

Browser extension that waits until the "Enable automatic completion" or "Complete pull request" dialog appears
on the pull request page of dev.azure.com.
It then enables the "Customize merge commit" option and removes the "Merged PR ...:" prefix from the title.

To use the extension with on-premise or *.visualstudio.com Azure DevOps instances, click the extension icon on a pull request page of that host. A permission dialog will appear—click "Allow" to grant the extension access to that instance.