[pushed] doc, fortran: Add a missing menu item.

[Thomas Koenig]

Am 27.10.24 um 00:15 schrieb Iain Sandoe:
> Tested on x86_64-darwin21 and linux, with makeinfo 6.7 pushed to trunk,
> thanks

Thanks!

For the record, makeinfo 6.8 did not show this as an error.

Best regards

	Thomas