Fix typo

Author: wooorm

readme.md

@@ -64,7 +64,7 @@ Find the first child before `index` (or `node`) in `parent`, that passes `test`
 
 ## Contribute
 
-See [`contribute.md` in `syntax-tree/unist`][contribute] for ways to get
+See [`contributing.md` in `syntax-tree/unist`][contributing] for ways to get
 started.
 
 This organisation has a [Code of Conduct][coc].  By interacting with this
@@ -96,6 +96,6 @@ repository, organisation, or community you agree to abide by its terms.
 
 [is]: https://github.com/syntax-tree/unist-util-is
 
-[contribute]: https://github.com/syntax-tree/unist/blob/master/contributing.md
+[contributing]: https://github.com/syntax-tree/unist/blob/master/contributing.md
 
 [coc]: https://github.com/syntax-tree/unist/blob/master/code-of-conduct.md