docs: fix removed ref to `deepspeed.initialize` #14037

Job	Run time
pl-cpu (macOS-14, lightning, 3.10, 2.1)	19m 21s
pl-cpu (ubuntu-20.04, lightning, 3.10, 2.1)	13m 58s
pl-cpu (windows-2022, lightning, 3.10, 2.1)	15m 34s
pl-cpu (macOS-14, lightning, 3.11, 2.2)	19m 30s
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.2)	13m 47s
pl-cpu (windows-2022, lightning, 3.11, 2.2)	16m 27s
pl-cpu (macOS-14, lightning, 3.11, 2.3)	23m 9s
pl-cpu (ubuntu-20.04, lightning, 3.11, 2.3)	13m 44s
pl-cpu (windows-2022, lightning, 3.11, 2.3)	16m 44s
pl-cpu (macOS-14, lightning, 3.12, 2.4)	20m 10s
pl-cpu (ubuntu-20.04, lightning, 3.12, 2.4)	19m 55s
pl-cpu (windows-2022, lightning, 3.12, 2.4)	17m 54s
pl-cpu (macOS-12, pytorch, 3.10, 2.1)	26m 0s
pl-cpu (ubuntu-22.04, pytorch, 3.10, 2.1)	14m 34s
pl-cpu (windows-2022, pytorch, 3.10, 2.1)	15m 45s
pl-cpu (macOS-13, lightning, 3.9, 2.1, oldest)	29m 39s
pl-cpu (ubuntu-20.04, lightning, 3.9, 2.1, oldest)	13m 22s
pl-cpu (windows-2022, lightning, 3.9, 2.1, oldest)	15m 25s
pl-cpu (macOS-14, pytorch, 3.9, 2.1)	19m 47s
pl-cpu (ubuntu-20.04, pytorch, 3.9, 2.1)	15m 4s
pl-cpu (windows-2022, pytorch, 3.9, 2.1)	15m 49s
	6h 15m 38s

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