Written lesson cleanup: Smart Contract Lottery

[gin]

Fix typos, formatting, and

• Add URL to Solidity docs on Order of Layout style guide 3-solidity-style-guide/+page.md

• Add a note about written lesson is using VRF V2 vs video lesson's VRF V2.5 8-implement-the-chainlink-vrf/+page.md

• Update written lesson from using VRF V2 to VRF V2.5 to match video lesson 21-deploy-a-mock-chainlink-vrf/+page.md

[EngrPips]

Hello, @gin, Thanks for this contribution. This will be attended to appropriately as soon as possible.