Drop mycplus.com iframe from Shortcode page

[chalin]

• Closes Consider removing/changing the iframe to mycplus.com #1468
• Drop the mycplus.com iframe from Shortcode page so now a page refresh, on my machines takes < 400 ms as compared to 5+ sec. The section immediately after contains an example of a {{< tab ... right=true text=true >}}, so nothing is lost.
• Whitespace cleanup in various code blocks

[deining]

I agree that www.mycplus.com needs to be replaced or removed.

What about replacing it with http://helloworldcollection.de:

{{< /tab >}}
{{< tab header="Reference" right=true text=true >}}
{{< iframe src="http://helloworldcollection.de" >}}
{{< /tab >}}

This site loads ways faster.

[chalin]

This was discussed during the March PSC meeting, and we agreed to drop the iframe, especially since it is secondary to that section (which is for tabbed panes). As remarked in the notes:

If we do choose to reintroduce an iframe, especially hidden under a tab, then it should be fully lazily loaded. (But I don't want to have to deal with that until BSv5 release of Docsy is out).

I'm going to merge this now since I keep hitting the iframe-loading delays during my BSv5 migration work, and I'm trying to wrap this up the BSv5 work ASAP. As mentioned above, we can look into re-introducing an iframe (if we feel that is important enough), provided it gets lazily loaded.