Class attributes in combined markdown

[skdelphix]

The markdown generated by mkdocscombine included attributes on many page titles, for example:

# Home {: .page-title}

and in some cases duplicated sections because of it:

## Prerequisites {: .page-title}

## Prerequisites

These attr_list items are not explicitly inside the source markdown, it appears they're coming from the 'pages' definition in mkdocs.yml.

How can I strip these out so they don't show up in the pdf?

[geosmart]

the same problem!