`@documentdescription': Summary text
------------------------------------
When producing HTML output for a document, `makeinfo' writes a
`<meta>' element in the `<head>' to give some idea of the content of
the document. By default, this "description" is the title of the
document, taken from the `@settitle' command (Note:settitle). To
change this, use the `@documentdescription' environment, as in:
@documentdescription
descriptive text
@end documendescription
This will produce the following output in the `<head>' of the HTML:
<meta name=description content="descriptive text">
`@documentdescription' must be specified before the first node of the
document.