**Do you want to request a *feature* or report a *bug*?**
Bug

**What is the current behavior?**
The documentation for [warnings](https://github.com/facebook/react/tree/master/docs/warnings) returns a 404

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/ebsrpraL/).**
https://cl.ly/080p0f1t400y

**What is the expected behavior?**
Redirect to correct documentation.

~~**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**~~

---
The workaround is to look at the cached version from a google search or check for markdown [here](https://github.com/facebook/react/tree/master/docs/warnings).
{
      allMarkdownRemark(limit: 1000) {
        edges {
          node {
            fields {
              redirect
              slug
            }
          }
        }
      }
    }
  `,
  );
  if (allMarkdown.errors) {
    console.error(allMarkdown.errors);
    throw Error(allMarkdown.errors);
  }
  allMarkdown.data.allMarkdownRemark.edges.forEach(edge => {
    const slug = edge.node.fields.slug;
    if (slug === '/index.html') {
      createPage({
        path: '/',
        component: homeTemplate,
        context: {
          slug,
        },
      });
    } else if (slug === 'docs/installation.html') {
      createPage({