Add documentation about unimplemented 7.4 commands #3421

Job	Run time
Build source distribution	1s
Generate wheels matrix	1s
Lint (Python 3.9)	1s
Lint (Python 3.10)	1s
Lint (Python 3.11)	1s
Test (Python 3.11, Redis 7.0, compiled)	1s
Lint (Python 3.12)	1s
Test (Python 3.11, Redis 7.2, compiled)	1s
Lint (Python 3.13)	1s
Test (Python 3.11, Redis 7.4, compiled)	1s
Test (Python 3.11, Redis latest, compiled)	1s
Test (Python 3.12, Redis 7.0, compiled)	1s
Test (Python 3.12, Redis 7.2, compiled)	1s
Test (Python 3.12, Redis 7.4, compiled)	1s
Test (Python 3.12, Redis latest, compiled)	1s
Test (Python 3.13, Redis 7.0, compiled)	1s
Test (Python 3.13, Redis 7.2, compiled)	1s
Test (Python 3.13, Redis 7.4, compiled)	1s
Test (Python 3.13, Redis latest, compiled)	1s
Test (Python 3.12, Redis latest)	1s
Test (Python 3.12, Redis 7.0, KeyDB)	1s
Test (Python 3.12, Redis 7.0, Dragonfly)	1s
Test (Python 3.12, Redis 7.0, Valkey)	1s
Test (Python 3.12, Redis 7.0, Redict)	1s
Test (Python pypy-3.9, Redis 7.0)	1s
Test (Python pypy-3.10, Redis 7.0)	1s
Build wheel on ${{ matrix.only }}	1s
Build pure python wheel	1s
upload_pypi_release	1s
upload_pypi	1s
Create Release	1s
	31s

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