Don't convert single \n to <br>

Author: leonardehrenfried

packages/graphiql-react/src/markdown.ts

@@ -1,6 +1,8 @@
 import MarkdownIt from 'markdown-it';
 
 export const markdown = new MarkdownIt({
-  breaks: true,
+  // we don't want to convert \n to <br> because in markdown a single newline is not a line break
+  // https://github.com/graphql/graphiql/issues/3155
+  breaks: false,
   linkify: true,
 });