Minimum(df[:value]) and maximum(df[:value]) not in the documentation

I just noticed that both minimum(df[:value]) and maximum(df[:value]) to retrive the minimum/maximum values of a column in a dataframe are not in the documentation… as they are not the standard min() max() function, it is not straightforward to find them… I think they should be added to the documentation of DataFrame…

maximum and minimum are standard functions for collections defined in Base.