Add Documentation URL for quick access via PyPI web (#2854)

Author: kerel-fs

pyproject.toml

@@ -10,6 +10,7 @@ readme.content-type = "text/markdown"
 keywords = ["virtual", "environments", "isolated", "testing"]
 license = "MIT"
 urls.Homepage = "http://tox.readthedocs.org"
+urls.Documentation = "https://tox.wiki"
 urls.Source = "https://github.com/tox-dev/tox"
 urls.Tracker = "https://github.com/tox-dev/tox/issues"
 urls."Release Notes" = "https://tox.wiki/en/latest/changelog.html"