Update CONTRIBUTING.md
Fix typo
@@ -156,7 +156,7 @@ In order to format the code:
### Documentation styleguide
We follow [NumPy documentation guidelines][numpydoc-guideline] for PyElastica documentation.
-If you are interested in contributing or modifying the documentation, please refer [docs-readme][docs-readme] file.
+If you are interested in contributing or modifying the documentation, please refer to the [docs-readme][docs-readme] file.
[beginner]: https://github.com/GazzolaLab/PyElastica/labels/good%20first%20issue
[help-wanted]: https://github.com/GazzolaLab/PyElastica/labels/help%20wanted
