x86/Documentation: Indent 'note::' directive for protocol version number note

x86/Documentation: Indent 'note::' directive for protocol version number note

The protocol version number note is between the protocol version table and
the memory layout section. As such, Sphinx renders the note directive not
only on the actual note, but until the end of doc.

Indent the directive so that only the actual protocol version number
note is rendered as such.

Fixes: 2c33c27fd603 ("x86/boot: Introduce kernel_info")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231106101206.76487-2-bagasdotme@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>