Diff syntax highlighting HTML spilling into content

[silverwind]

https://try.gitea.io/silverwind/updates/commit/9f342114d7a6bb087ff777a983d0e03b41873b07
silverwind/updates@9f34211

On Line 88 of test.js the parts nx"> and k"> related to syntax highlighting markup should not be visible. Source HTML:

<span class="<span class=" removed-code"="">nx"&gt;resultValue</span>

<span class="<span class=" added-code"="">k"&gt;typeof</span>

cc: @mrsdizzie

[mrsdizzie]

Good catch, this is side effect from #12205

Made a PR that should fix this if you could please test