Render to word C++ as monospaced

Hi all,

in the last preview of asciidoctor I was able to write `C++` to render it as monospaced and I had not trouble with it.

In the actual version 1.5.0 it fails because the ++ ist recognized as formatting.

What is the best way to render it correctly as monospaced (code)?

Reading the docs carefully I think this is a bug in asciidoctor because it should be an inline literal passthrough.

Setting :compat-mode: solves this issue !