chore(README): fix typo (#3877)

README.md

@@ -119,7 +119,7 @@ Run `npm run perf_micro [operator]` to run micro performance test benchmarking o
 ## Adding documentation
 RxNext uses [ESDoc](https://esdoc.org/) to generate API documentation. Refer to ESDoc's documentation for syntax. Run `npm run build_docs` to generate.
 
-At the moment we are trying to improve the documentation. For this purpose the Documentation is in a seperate [GitHub Repostory](https://github.com/ReactiveX/rxjs-docs).
+At the moment we are trying to improve the documentation. For this purpose the Documentation is in a separate [GitHub Repository](https://github.com/ReactiveX/rxjs-docs).
 For a quick instruction take a look at the [documentation guidelines](https://github.com/ReactiveX/rxjs-docs/blob/master/DOCUMENTATION_GUIDELINES.md).
 We are really happy about any type of contributions!