How to link an issue to a pull request: write Closes #number so it closes on merge

In AngusGit, an issue and a pull request can be linked. Write Closes #number in the pull request title or description, and each page lists the other. After the merge, the issue closes on its own. This article lists the English keywords that work, explains that only the title or description counts for the link, and shows what to check when the issue does not close.