docs: fix broken TOC links and grammar in readme

- Remove non-existent 'Git commit messages' and 'Formatting and Validation' sections from Table of Contents
- Add missing 'Placement of the images' section to TOC
- Fix grammar: 'should stored' -> 'should be stored'

Author: NoamHarel1

readme.md

@@ -17,9 +17,8 @@ Looking to file bugs, request features or send feedback? File an issue or vote o
   - [How Can You Contribute?](#how-can-you-contribute)
   - [Getting Started](#getting-started-1)
 - [Project Conventions](#project-conventions)
-  - [Git commit messages](#git-commit-messages)
+  - [Placement of the images](#placement-of-the-images)
   - [Styles](#styles)
-    - [Formatting and Validation](#formatting-and-validation)
 
 ## Project Details
 
@@ -104,7 +103,7 @@ Please ensure that your code adheres to the existing code style and conventions
 
 ### Placement of the images:
 
-In order to get the benefits of the image optimization, these images should stored inside the public folder like `public/images/posts/..` or `public/images/docs/..` (except for the statically imported images and remote images). Then these images can be referenced in the src attribute of the `<Image />` element.
+In order to get the benefits of the image optimization, these images should be stored inside the public folder like `public/images/posts/..` or `public/images/docs/..` (except for the statically imported images and remote images). Then these images can be referenced in the src attribute of the `<Image />` element.
 
 ### Styles