docs/sphinx: Fix syntax issues in hyperlaunch.rst

docs/sphinx: Fix syntax issues in hyperlaunch.rst

sphinx-build reports:

  docs/designs/launch/hyperlaunch.rst:111: WARNING: Title underline too short.
  docs/designs/launch/hyperlaunch.rst:203: WARNING: Unexpected indentation.
  docs/designs/launch/hyperlaunch.rst:216: WARNING: Unexpected indentation.

Nested lists require newlines as delimiters.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>