Update README.md (dotnet#2456)

seperate -> separate

Author: Ikko Eltociear Ashimine

docs/docfx/README.md

@@ -12,7 +12,7 @@ The build will produce a series of HTML files in the `_site` directory. Many of
 
 ## Publishing the docs
 
-The docs are automatically built and published by a [GitHub Action](https://github.com/microsoft/reverse-proxy/blob/main/.github/workflows/docfx_build.yml) on every push to `release/latest`. The built `_site` directory is pushed to the `gh-pages` branch and served by [https://microsoft.github.io/reverse-proxy/](https://microsoft.github.io/reverse-proxy/). Maintaining a seperate branch for the released docs allows us to choose when to publish them and with what content, and without modifying the build scripts each release.
+The docs are automatically built and published by a [GitHub Action](https://github.com/microsoft/reverse-proxy/blob/main/.github/workflows/docfx_build.yml) on every push to `release/latest`. The built `_site` directory is pushed to the `gh-pages` branch and served by [https://microsoft.github.io/reverse-proxy/](https://microsoft.github.io/reverse-proxy/). Maintaining a separate branch for the released docs allows us to choose when to publish them and with what content, and without modifying the build scripts each release.
 
 Doc edits for the current public release should go into that release's branch (e.g. `release/1.0.0-preview3`) and merged forward into `main` and `release/latest`.