new `ManualEstimator` tests and minor doc corrections #1463

Job	Run time
Julia lts - ubuntu-latest - x64 - pull_request	37m 5s
Julia 1 - ubuntu-latest - x64 - pull_request	40m 2s
Julia pre - ubuntu-latest - x64 - pull_request	1h 4m 45s
	2h 21m 52s

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