Update prettier (#22520)

* Update prettier to latest version

* Run 'yarn format' from root of project

* Remove prettier-ignore for nested markdown

* Fix starters

* Fix benchmarks

* Fix examples

* Fix integration-tests

* Update eslint-config-prettier & eslint-plugin-prettier

* Fix linting

* Update all .prettierrc

* Run Prettier on full codebase

* Remove unnecessary .prettierrc & .prettierignore files

* Update Prettier script

* Update snapshots

* Revert snapshot

* Revert "Update Prettier script"

This reverts commit 008eb996

* Update snapshot

* Update docs/blog/2018-08-09-swag-store/index.md

Co-Authored-By: Dima An <[email protected]>

Co-authored-by: Dima An <[email protected]>

Author: gatsbybot

.prettierrc

@@ -1,7 +1,4 @@
 {
-  "endOfLine": "lf",
-  "semi": false,
-  "singleQuote": false,
-  "tabWidth": 2,
-  "trailingComma": "es5"
+  "arrowParens": "avoid",
+  "semi": false
 }

content/posts/hello-world.mdx

@@ -11,21 +11,21 @@ Delete me, and get writing!
 module.exports = {
   plugins: [
     "gatsby-theme-blog", // highlight-line
-    "gatsby-theme-notes"
-  ]
-};
+    "gatsby-theme-notes",
+  ],
+}
 ```
 
 This is another paragraph after the code block.
 
 ## This is a secondary heading
 
 ```jsx
-import React from "react";
-import { ThemeProvider } from "theme-ui";
-import theme from "./theme";
+import React from "react"
+import { ThemeProvider } from "theme-ui"
+import theme from "./theme"
 
 export default props => (
   <ThemeProvider theme={theme}>{props.children}</ThemeProvider>
-);
+)
 ```