Try to fix mermaid parse issue

Author: tylerlong

package.json

@@ -1,6 +1,6 @@
 {
   "name": "markdown-it-mermaid",
-  "version": "0.1.5",
+  "version": "0.1.6",
   "description": "Mermaid plugin for markdown-it.",
   "main": "src/index.js",
   "scripts": {

src/index.js

@@ -6,7 +6,7 @@ const mermaidChart = (code) => {
   window.mermaid.parseError = (error, hash) => {
     mermaidError = error
   }
-  if (window.mermaid.parse(code)) {
+  if (window.mermaid.parse(code) || mermaidError === null) {
     return `<div class="mermaid">${code}</div>`
   } else {
     return `<pre>${mermaidError}</pre>`
@@ -31,7 +31,7 @@ const MermaidPlugin = (md) => {
   const temp = md.renderer.rules.fence.bind(md.renderer.rules)
   md.renderer.rules.fence = (tokens, idx, options, env, slf) => {
     const token = tokens[idx]
-    const code = token.content.trim() + '\n' // git graph requires line break at the end
+    const code = token.content.trim()
     if (token.info === 'mermaid') {
       return mermaidChart(code)
     }