Randomize is declared and implemented in the GAP library, but documentation is in orb package

[fingolfin]

I suspect Randomize used to be in the orb package but then was migrated to the GAP library -- except the documentation was not moved.

So most likely the fix is to move the documentation, too.

[fingolfin]

Also, the order of arguments is "wrong": we tried to have the random source be first argument for as many things as possible, but here it is the second (final) argument. However, I think we could easily fix this by changing the documentation and implementation to reverse this (implemented using InstallMethodWithRandomSource), and then providing a single InstallOtherMethod with the old order, which redispatches to the new order (and prints an InfoObsolete warning).