Configure Prettier for Markdown formatting (#1112)

docs/prettier.config.js

@@ -1,4 +1,13 @@
 module.exports = {
   trailingComma: 'none',
-  singleQuote: true
+  singleQuote: true,
+  overrides: [
+    {
+      files: '*.md',
+      options: {
+        printWidth: 80,
+        proseWrap: 'always'
+      }
+    }
+  ]
 };