Update README to use correct generation command for tsconfig-references

[sapphi-red]

pnpm run --filter=tsconfig-reference generate-json and pnpm run --filter=tsconfig-reference generate-markdown were written in the README, but these were wrong.

TypeScript-Website/packages/tsconfig-reference/package.json

Lines 11 to 15 in c65adad

	"generate:json": "pnpm generate:json:tsconfig && pnpm generate:json:cli && pnpm generate:json:schema && pnpm generate:json:msbuild",
	"generate:md:tsconfig": "tsc --build && node --experimental-json-modules scripts/tsconfig/generateMarkdown",
	"generate:md:cli": "tsc --build && node --experimental-json-modules scripts/cli/generateMarkdown",
	"generate:md:msbuild": "tsc --build && node --experimental-json-modules scripts/msbuild/generateMarkdown",
	"generate:md": "pnpm generate:md:tsconfig && pnpm generate:md:cli && pnpm generate:md:tsconfig",

This PR replaces them with the correct command.