net: dns_resolver: Use reST bullet list for features list

Features overview list uses an asterisk in parentheses (``(*)``)
as bullet list marker, which isn't supported by Sphinx as proper
bullet. Replace it with just asterisk.

Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20250924020626.17073-2-bagasdotme@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>