Fix product example mobile navbar toggler

[julien-deramond]

Description

This PR fixes the second issue described in #39656:

"Product example": when screen is small (mobile for example), menu does not work. I click the button but nothing happens.

Indeed, the IDs started with a "#" which caused an issue when referenced by data-bs-toggle.
Other references starting with a "#" were also wrong in this same document and have been fixed.

Type of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the contributing guidelines
• My code follows the code style of the project (using npm run lint)
• My change introduces changes to the documentation
• (N/A) I have updated the documentation accordingly
• (N/A) I have added tests to cover my changes
• All new and existing tests passed

Live previews

• https://deploy-preview-39657--twbs-bootstrap.netlify.app/docs/5.3/examples/product/ (please check the mobile mode and the offcanvas)

Related issues

Closes #39656