Fix typos

Author: Artem Innokentiev

EN.md

@@ -9,8 +9,8 @@
   - [Imports](#imports)
   - [Files `__init__.py`](#files-__init__py)
   - [Docstrings](#docstrings)
-- [About Pull Request](#about-pull-request)
-  - [Creating Pull Request](#creating-pull-request)
+- [About Pull Requests](#about-pull-requests)
+  - [Creating Pull Requests](#creating-pull-requests)
   - [Refactoring and Pull Requests](#refactoring-and-pull-request)
   - [Pull Request Size](#pull-request-size)
 - [About tooling](#about-tooling)