fix(session): move cookie name to root level cookieName config

[philippe-desplats]

Summary

• Corrects the session documentation to reflect the actual API: cookieName is a root-level config option, not cookie.name
• Updates the default config example to show cookieName: 'adonis-session' instead of nested cookie.name
• Documents cookieName as a proper config option in the reference section
• Removes the incorrect cookie.name option from the Cookie configuration section

Changes

• content/guides/basics/session.md:
  • Moved cookieName to root level in the default config example
  • Removed name property from the nested cookie object
  • Added cookieName to the configuration options documentation
  • Removed incorrect cookie.name option documentation
  • Updated the cookie option description (removed mention of "cookie name")

[thetutlage]

Looks good. Can you please remove the package-lock.json file from changes, as that is not relevant to this change

[philippe-desplats]

Done! I removed package-lock.json and .env.example from the changes. The PR now only contains the session.md fix.

[thetutlage]

Fixed in one of the other commits!