Update broken link to amending-a-commit-guide.md

contributing.md

@@ -21,5 +21,5 @@ A lot of times, making a PR adhere to the standards above can be difficult.
 If the maintainers notice anything that we'd like changed, we'll ask you to
 edit your PR before we merge it. There's no need to open a new PR, just edit
 the existing one. If you're not sure how to do that,
-[here is a guide](https://github.com/RichardLitt/docs/blob/master/amending-a-commit-guide.md)
+[here is a guide](https://github.com/RichardLitt/knowledge/blob/master/github/amending-a-commit-guide.md)
 on the different ways you can update your PR so that we can merge it.