[vscode] VSCode Syntax Highlighting for Virgil

[btwj]

Visual Studio Code syntax highlighting for Virgil

• Uses tree-sitter to parse Virgil files, and walks the AST to output semantic tokens

[titzer]

@btwj If you want to mark this as no longer a draft, I'll merge it.

[titzer]

@btwj If you want to mark this as no longer a draft, I'll merge it.

Nm, I have the power. Going to merge. Feel free to send follow up PRs.