MAINT: Narrow return type for `ContentStream.operations` (#2941) #5594

Job	Run time
Check code style issues	40s
pytest on windows	6m 26s
Build & verify package	10s
pytest on 3.8 (crypto-lib: cryptography)	5m 24s
pytest on 3.9 (crypto-lib: cryptography)	5m 28s
pytest on 3.10 (crypto-lib: cryptography)	5m 19s
pytest on 3.11 (crypto-lib: cryptography)	4m 58s
pytest on 3.12 (crypto-lib: cryptography)	6m 37s
pytest on 3.13 (crypto-lib: cryptography)	6m 45s
pytest on 3.8 (crypto-lib: pycryptodome)	5m 11s
pytest on 3.8 (crypto-lib: none)	5m 11s
Combine & check coverage.	24s
	52m 33s

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