add a page break to avoid a single line para

Clarify PTE update text

updating with public review feedback

Issue 15

Detect Docker robustly

"&> /dev/null" works as a redirection from stdout/stderr to /dev/null
in Bash but not in POSIX shell (considered as an asynchronous execution
and the result of the "command" command cannot be retrieved).

As a result, it always assumes that Docker always exists.

This commit makes the redirection robust and portable (makes it possible
to detect "no Docker" condition correctly).

Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>

Editorial updates 

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: Rafael Sene <rafael@riscv.org>

PR for issue #5

issue 3

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

issue 4

issue 6

Changing text "behaves as though Svadu is not implemented" to "behaves as though Svadu were not implemented" to match similar text  in Priv. spec and to address concern raised in issue #2 

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>

Signed-off-by: ved-rivos <91900059+ved-rivos@users.noreply.github.com>