Clarify that Windows startup-managed VHD/VHDX files, including Dev Drive backing images, cannot live on system favorite volumes because they are accessed before those volumes are mounted.
Document that native-boot VHD/VHDX files also cannot live on system favorite volumes and remain subject to the existing VeraCrypt pre-boot authentication limitation for operating systems installed within VHD/VHDX files.
Mention a delayed/retrying attach workaround for non-boot-critical VHD/VHDX files after VeraCryptSystemFavorites mounts the host volume.
Closes#1605.
* Documentation: Remove XHTML spec and fix errors
None of the docs follow the XHTML specification, which means
that programs that expect this (such as Gnome Web) as it is advertised
as such, will completely fail to parse it as it is incorrect syntax. So
it is removed.
* Remove .chm files
