Example block has no format in Asciidoc
### Summary
Example blocks in Asciidoc doesn't render in any different way than normal paragraphs.
### Steps to reproduce
1. Create a simple asciidoc readme file like this:
```
.Example block
====
This is an example block.
====
```
2. Push to gitlab and see the result. The block is rendered like a normal paragraph.
You can check with asciidoctor or any other asciidoc renderer that example blocks have a particular style.
Alternatively, you can check this by looking at this example project: https://gitlab.com/joanq/asciidocexampleblockbug
### What is the current *bug* behavior?
The block is rendered like a normal paragraph.
### What is the expected *correct* behavior?
There should be some kind of style, similar to an admonition block without icon.
### Output of checks
This bug happens on GitLab.com
issue