[Selectable Components: Structured List - Style] Website Doc

[Kritvi-bhatia17]

Closes #744

Acceptance criteria

Update the Structured List website(Style tab) documentation with what came out of our final design solutions.

---

STYLE TAB

Color section

• Add an image for both Transparent and Background structured list (enabled states)
• Add the color specs for structured list with background as 'optional'
• Make sure the tables have the correct color tokens

Interactive states section

• Add an image for both Transparent and Background structured list (enabled states)
• Add the interactive specs for structured list with background as 'optional'
• Make sure the tables have the correct color tokens

Typography section

• "List text" -> "Row text"

Structure section

• Update the structure table specs
• Add Default structure & Selectable structure sections with description and images each

• Add Size section with description and images each

---

• PR Review -> Merge

[github-actions]

Thank you for submitting a feature request. Your proposal is open and will soon be triaged by the Carbon team.

If your proposal is accepted and the Carbon team has bandwidth they will take on the issue, or else request you or other volunteers from the community to work on this issue.