docs: add version added flags to deep agents documentation #11130

Job	Run time
check-cross-refs	26s
check-generated-files	19s
test (3.13) / make test #3.13	23s
lint (3.13) / make lint #3.13	20s
links (3.13) / Documentation Build & Link Check (Python 3.13)	2m 15s
	3m 43s

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