Fix links in readme.md

Author: wooorm

readme.md

@@ -215,7 +215,7 @@ should however be entirely stripped from the tree.
 
 ## Contribute
 
-See [`contribute.md` in `syntax-tree/unist`][contribute] for ways to get
+See [`contribute.md` in `syntax-tree/hast`][contribute] for ways to get
 started.
 
 This organisation has a [Code of Conduct][coc].  By interacting with this
@@ -249,6 +249,6 @@ repository, organisation, or community you agree to abide by its terms.
 
 [schema-github]: lib/github.json
 
-[contribute]: https://github.com/syntax-tree/unist/blob/master/contributing.md
+[contribute]: https://github.com/syntax-tree/hast/blob/master/contributing.md
 
-[coc]: https://github.com/syntax-tree/unist/blob/master/code-of-conduct.md
+[coc]: https://github.com/syntax-tree/hast/blob/master/code-of-conduct.md