style: pre-commit fixes

CONTRIBUTING.md

@@ -470,7 +470,7 @@ GitHub does some magic with particular filenames. In particular:
 
 - The first page people see when they go to [our GitHub page](https://github.
   com/pybamm-team/PyBaMM) displays the contents of [README.md]
-  (https://github.com/pybamm-team/PyBaMM/blob/develop/README.md), which is 
+  (https://github.com/pybamm-team/PyBaMM/blob/develop/README.md), which is
   written in the [Markdown](https://github.
   com/adam-p/markdown-here/wiki/Markdown-Cheatsheet) format. Some guidelines can be found [here](https://docs.github.com/articles/about-readmes/).
 - The license for using PyBaMM is stored in [LICENSE](https://github.com/pybamm-team/PyBaMM/blob/develop/LICENSE.txt), and [automatically](https://docs.github.com/articles/adding-a-license-to-a-repository/) linked to by GitHub.