docs(www): Change to Gatsby develop

docs/docs/why-gatsby-uses-graphql.md

@@ -49,7 +49,7 @@ exports.createPages = ({ actions: { createPage } }) => {
 }
 ```
 
-After running `npm run develop`, you’ll see the following at `localhost:8000/no-data/`:
+After running `gatsby develop`, you’ll see the following at `localhost:8000/no-data/`:
 
 ![Screenshot of the page generated by the previous code snippet.](./images/why-gql-no-data.png)
 
@@ -102,7 +102,7 @@ const WithContext = ({ pageContext }) => (
 export default WithContext
 ```
 
-Start the development server with `npm run develop` and visit `localhost:8000/page-with-context/` to see the created page:
+Start the development server with `gatsby develop` and visit `localhost:8000/page-with-context/` to see the created page:
 
 ![Screenshot of a page with hard-coded context.](./images/why-gql-with-context.png)
 
@@ -192,7 +192,7 @@ const Product = ({ pageContext }) => (
 export default Product
 ```
 
-Run `npm run develop`, then open `localhost:8000/product/space-socks/` to see one of the generated products.
+Run `gatsby develop`, then open `localhost:8000/product/space-socks/` to see one of the generated products.
 
 ![Screenshot of a rendered product page.](./images/why-gql-product-json.png)
 
@@ -265,12 +265,12 @@ module.exports = {
 To check that this worked, let’s use the GraphQL Playground, which is available during development, by running:
 
 ```
-GATSBY_GRAPHQL_IDE=playground yarn develop
+GATSBY_GRAPHQL_IDE=playground gatsby develop
 ```
 
 > **NOTE:** The `GATSBY_GRAPHQL_IDE=playground` part of this command is optional. Adding it enables the GraphQL Playground instead of GraphiQL, which is an older interface for exploring GraphQL.
 
-You can explore the available data using the “Docs” tab at the right.
+You can explore the available data schema using the “Docs” tab at the right.
 
 One of the available options is `allProductsJson`, which contains “edges”, and those contain “nodes”.
 
@@ -337,7 +337,7 @@ exports.createPages = async ({ actions: { createPage }, graphql }) => {
 }
 ```
 
-You need to use the `graphql` helper that’s available to the [`createPages` API](/docs/node-apis/#createPages) to execute the query. To make sure that the result of the query comes back before continuing, use [`async`/`await`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function).
+You need to use the `graphql` helper that’s available to the [`createPages` Node API](/docs/node-apis/#createPages) to execute the query. To make sure that the result of the query comes back before continuing, use [`async`/`await`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function).
 
 The results that come back are very similar to the contents of `data/products.json`, so you can loop through the results and create a page for each.
 
@@ -396,7 +396,7 @@ A few notes about this file:
 3. The query uses a [GraphQL fragment](https://www.gatsbyjs.org/packages/gatsby-image/#fragments) to query all the required data for optimized images. GraphQL fragments _do not work_ in the GraphQL Playground.
 4. The `img` tag has been swapped out for a `gatsby-image` component named `Image`. Instead of a `src` attribute, it accepts an object with optimized image data.
 
-Save this file, run `npm run develop`, then open `localhost:8000/gql/purple-hat/`:
+Save this file, run `gatsby develop`, then open `localhost:8000/gql/purple-hat/`:
 
 ![Lazy loaded image of an angry cat wearing the purple hat.](./images/why-gql-images.gif)