This template in Markdown format has been superseded by the forms in the
`.github./ISSUE_TEMPLATE` directory. When viewing this file in the
GitHub UI, it shows a warning:

> You are using an old version of issue templates. Please update to the
> new issue template workflow. [Learn more][1]

[1]: https://docs.github.com/articles/about-issue-and-pull-request-templates

All of these direct links to our old Markdown-based issue templates are
broken and just lead to an empty form. I could link directly to the
relevant new yml template, but standardizing on `/issues/new/choose`
seems safer as it'll continue working even if we change the available
templates.