v2-docs: Add docs for transformed data #1023

Job	Run time
build-vegafusion-wasm	5m 38s
check-rust	3m 46s
build-vegafusion-python-linux-arm64	3m 30s
build-vegafusion-python-linux-64	2m 54s
build-vegafusion-python-win-64	24m 33s
build-vegafusion-python-osx-64	19m 28s
check-vegafusion-python	10m 0s
test-rust (ubuntu-20.04)	25m 41s
build-vegafusion-python-osx-arm64	14m 21s
test-rust (windows-2022)	39m 7s
build-vegafusion-server-linux-64	8m 45s
test-rust (macos-14)	27m 9s
build-vegafusion-server-linux-arm64	2m 14s
build-vegafusion-server-osx-64	20m 15s
build-vegafusion-server-osx-arm64	12m 30s
build-vegafusion-server-win-64	22m 36s
test-vegafusion-python-linux-64	25m 42s
test-vegafusion-python-osx-arm64	1m 4s
test-vegafusion-python-win-64	2m 0s
	4h 31m 13s

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