It’s called Markdown. If you know how to use it, it’s very convenient, but if not, it can cause all kinds of unexpected effects. It’s also the reason that **test** is formatted as test. You can often force new lines by ending the line with two spaces or a backslash character. Let’s test:
This is a line
And this is another line
In this case it was a backslash character. So what I typed is:
This is a line\
And this is another line
With spaces:
This is a line
And this is another line
It’s off by default, but activated when you end your search query with a question mark. That option can be turned off.