docs: integrate Vale for documentation linting (#2242)

* added value rules

* resolved errors raised by vale

* added github action

* fixes to github action

* added details in contribution guidelines

* added rule for numbers

* limited checks to errors

docs/content/quickstart/quick-start-docker.md

@@ -1,3 +1,4 @@
+<!-- vale off -->
 # Quickstart w. Docker
 
 This quick start is intended for developers, that have already configured their local development environment and familiarised them selves with all the technologies and frameworks used throughout the Medusa eco-system.
@@ -84,3 +85,5 @@ Add custom endpoint to your Medusa project
 Install and configure additional plugins
 
 Build a storefront using our [Gatsby Starter](https://github.com/medusajs/gatsby-starter-medusa)
+
+<!-- vale on -->

docs/content/quickstart/quick-start.md

@@ -45,7 +45,7 @@ You can install Node from the [official website](https://nodejs.org/en/).
 
 ### Test Your Server
 
-After these 3 steps and in only a couple of minutes, you now have a complete commerce engine running locally. You can test it out by sending a request using a tool like Postman or through the command line:
+After these three steps and in only a couple of minutes, you now have a complete commerce engine running locally. You can test it out by sending a request using a tool like Postman or through the command line:
 
 ```bash
 curl localhost:9000/store/products | python -m json.tool
@@ -79,7 +79,7 @@ You can learn more about configuring your server and loading environment variabl
 
 ## What's next :rocket:
 
-- Install our [Next.js](../starters/nextjs-medusa-starter.md) or [Gatsby](../starters/gatsby-medusa-starter.md) storefronts to set up your ecommerce storefront quickly.
+- Install the [Next.js](../starters/nextjs-medusa-starter.md) or [Gatsby](../starters/gatsby-medusa-starter.md) storefronts to set up your ecommerce storefront quickly.
 - Install the [Medusa Admin](../admin/quickstart.md) to supercharge your ecommerce experience with easy access to configurations and features.
 - Check out the [API reference](https://docs.medusajs.com/api/store) to learn more about available endpoints available on your Medusa server.
 - Install [plugins](https://github.com/medusajs/medusa/tree/master/packages) for features like Payment, CMS, Notifications, among other features.