Fixes swagger-editor/#1502.

Change logic for markdown rendering to:

1. Convert source markdown to HTML
2. Sanitize HTML
3. Send sanitized HTML to markdown renderer

src/core/plugins/oas3/wrap-components/markdown.js

@@ -1,11 +1,26 @@
 import React from "react"
 import ReactMarkdown from "react-markdown"
+import { Parser, HtmlRenderer } from "commonmark"
 import { OAS3ComponentWrapFactory } from "../helpers"
 import { sanitizer } from "core/components/providers/markdown"
 
-export default OAS3ComponentWrapFactory(({ source }) => { return source ? (
-  <ReactMarkdown
-    source={sanitizer(source)}
-    className={"renderedMarkdown"}
-    />
-) : null})
+export default OAS3ComponentWrapFactory(({ source }) => { 
+  if ( source ) {
+    const parser = new Parser()
+    const writer = new HtmlRenderer()
+    const html = writer.render(parser.parse(source || ""))
+    const sanitized = sanitizer(html)
+
+    if ( !source || !html || !sanitized ) {
+        return null
+    }
+
+    return (
+      <ReactMarkdown
+        source={sanitized}
+        className={"renderedMarkdown"}
+      />
+    )
+  }
+  return null
+})