feat(gatsby-source-contentful): enable RichText for all users (gatsby…

…js#10301)

Now that RichText is in beta and more stable we can remove the opt-in flag to make it available for all users

packages/gatsby-source-contentful/README.md

@@ -135,10 +135,20 @@ like the following:
 
 ## **Beta** [Contentful Rich Text](https://www.contentful.com/developers/docs/concepts/rich-text/)
 
-If you want to use the new Rich Text feature you can opt-in by setting the following environment variable:
+Rich text feature is supported in this source plugin, if you want to serialize the field content to html you can add the plugin `@contentful/gatsby-transformer-contentful-richtext`.
 
-```sh
-export GATSBY_CONTENTFUL_RICH_TEXT='enabled'
+After adding the transformer plugin you can use the following query to get the html output:
+
+```
+{
+ allContentfulBlogPost {
+ bodyRichText {
+ childContentfulRichText {
+ html
+ }
+ }
+ }
+}
 ```
 
 [dotenv]: https://github.com/motdotla/dotenv

packages/gatsby-source-contentful/src/normalize.js

@@ -402,7 +402,6 @@ exports.createContentTypeNodes = ({
  delete entryItemFields[entryItemFieldKey]
  } else if (
  fieldType === `RichText` &&
- process.env.GATSBY_CONTENTFUL_RICH_TEXT === `enabled` &&
  _.isPlainObject(entryItemFields[entryItemFieldKey])
  ) {
  const richTextNode = prepareStructuredTextNode(