Docs: install commands should use @babelize/ and drop the stray "bash" text #54

Two problems in every install snippet on elements.babelize.co:

1. Wrong registry namespace. Snippets say npx shadcn@latest add @elements/<name>. The official shadcn/ui registry directory now lists us as @babelize (feat(registry): add community registries shadcn-ui/ui#12347), so people arriving from shadcn's directory copy a command that does not match. Use npx shadcn@latest add @babelize/<name> (and the pnpm/yarn/bun variants).
2. "bash" leaks into the command. The rendered snippet reads bash npx shadcn@latest add …; the code-fence language is being rendered as text. Copying it gives a broken command.

Affects ~36 occurrences under content/docs and src.