We were only supporting the main name of each HighlightJS language. So, by default, you could not use `js` or `jsx` to highlight Javascript, given they are aliases for `javascript`.
This PR adds a list of aliases as a constant to core (built via a rake task), and then checks against the `highlighted_languages` site settings plus the list of aliases when processing a code block.
Also, the change in insert-hyperlink (from `this.linkUrl.indexOf("http") === -1` to `!this.linkUrl.startsWith("http")`) was intentional fix: we don't want to prevent users from looking up topics with http in their titles.
Allows to write custom code blocks:
```
```mermaid height=200,foo=bar
test
```
```
Which will then get converted to:
```
<pre data-code-wrap="mermaid" data-code-height="200" data-code-foo="bar">
<code class="lang-nohighlight">
test
</code>
</pre>
```
