rootfstype and rootflags not documented in kernel_parameters.txt

Hello!

In kernel 2.4.19 the rootfstype and rootflags option isn't documented, and it isn't an easy task to search them out from the source (espicially if the one who do it is not a kernel hacker...).

Please give them two line at least. And in the BootPrompt-HOWTO this options also can't be found.

Thanks,
Gergely