This question is a little old but I have been trying to figure this out for using the Gitlab extension for math equations and the short answer is I don't think you can do it out of the box.
The maven-site-plugin uses the doxia-module-markdown module for markdown which uses Flexmark internally but it is pre-configured with the extensions that it uses for this.
Here's a link to the code and the exact snippet from
// Initialize the Flexmark parser and renderer, once and for all
static
{
MutableDataSet flexmarkOptions = new MutableDataSet();
// Enable the extensions that we used to have in Pegdown
flexmarkOptions.set( com.vladsch.flexmark.parser.Parser.EXTENSIONS, Arrays.asList(
EscapedCharacterExtension.create(),
AbbreviationExtension.create(),
AutolinkExtension.create(),
DefinitionExtension.create(),
TypographicExtension.create(),
TablesExtension.create(),
WikiLinkExtension.create(),
StrikethroughExtension.create()
) );
// ...
}
I think that you could possibly fork this project, add the extensions you need, and add it as a dependency to the maven-site-plugin and it might work like this:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-site-plugin</artifactId>
<version>3.8.2</version>
<dependencies>
<dependency>
<groupId>${my-forked-groupId}</groupId>
<artifactId>${my-forked-artifactId}</artifactId>
<version>${my-forked-version}</version>
</dependency>
</dependencies>
</plugin>
This in my opinion is less than ideal and I will probably be exploring other (non-maven) options to get the result I'm looking for but will probably still try this out in the next day or so and if I get it working I'll send a link to the code in case anybody else can benefit from it.