Update README.md

Author: hubwriter

contributing/README.md

@@ -5,7 +5,7 @@ Check out our [contributing guide](../CONTRIBUTING.md) to see all the ways you c
 Here, you'll find additional information that might be helpful as you work on a pull request in this repo.
 
 - [development](./development.md) - steps for getting this app running on your local machine
-- [codespace](./codespaces.md) - use GitHub Codespaces to work on documentation markdown files
+- [codespace](./codespace.md) - use GitHub Codespaces to work on documentation markdown files
 - [content markup reference](./content-markup-reference.md) - how to use markup and features specific to the GitHub Docs site 
 - [content style guide](./content-style-guide.md) - style guidance specific to GitHub Docs content and additional resources for writing clear, helpful content
 - [content model](./content-model.md) - the content types that make up GitHub Docs and how to write them