doc: clarify sqlite bare named parameter default

[sanzofr]

Fixes: #61823

Clarify that allowBareNamedParameters defaults to true, so bare named
parameters are allowed by default. The previous wording incorrectly implied
that the prefix character is required unless bare named parameters are
explicitly enabled.

[nodejs-github-bot]

Review requested:

• @nodejs/sqlite

[trivikr]

@sanzofr Can you please sign the commit and force push?

It's required as per instructions

Your commit must contain the Signed-off-by line with your name and email address as an acknowledgement that you agree to the Developer Certificate of Origin.

[sanzofr]

Done. i've signed off the commit and force-pushed the changes.

[trivikr]

I just noticed that there's an existing PR which was posted before this #62009, and was linked in the issue.