Fix use of the default role in a news entry. (GH-92500)

(cherry picked from commit 88831728)

Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com>

Misc/NEWS.d/next/Documentation/2022-04-24-22-09-31.gh-issue-91888.kTjJLx.rst

-Add a new `gh` role to the documentation to link to GitHub issues.
+Add a new ``gh`` role to the documentation to link to GitHub issues.