chore: remove unnecessary vercel.json from docs #13042

Job	Run time
Determine jobs to run	38s
Go Unit Tests	0s
Build Turborepo	0s
Go linting	0s
Turborepo Examples	0s
JS Package Tests	0s
Rust lints	0s
Turbopack TypeScript files	0s
Turborepo rust check	0s
Formatting	0s
Check next-swc	0s
Turbopack rust check	0s
Turborepo Rust testing on ${{ matrix.os.name }}	0s
Go Integration Tests	0s
Turborepo E2E Tests	0s
Turborepo rust clippy	0s
Benchmark and compare Turbopack performance on ${{ matrix.os.title }}	0s
Benchmark on ${{ matrix.bench.name }}	0s
Turbopack Rust testing benchmarks on ${{ matrix.os.name }}	0s
Turbopack Rust testing benchmarks on ubuntu	0s
Turbopack Rust testing on ubuntu	0s
Turbopack rust clippy	0s
Turbopack Rust testing on ${{ matrix.os.name }}	0s
Store benchmark result	0s
Ok	4s
Upload Test results	38s
Done	4s
Cleanup / cleanup	2s
	1m 26s

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