[docs] avoid npm-specific `npx` wording in package manager tabs

[GivenBY]

The Prisma Postgres quickstart includes package manager tabs npm, pnpm, yarn, bun but the text says:

You can now invoke the Prisma CLI by prefixing it with npx

This wording is npm-specific and becomes incorrect/confusing for users following the pnpm, yarn, or bun tabs.

Examples:

• npm → npx prisma
• pnpm → pnpm dlx prisma
• yarn → yarn dlx prisma
• bun → bunx --bun prisma

fix

Replace the sentence

You can now run Prisma CLI commands using your package manager: