Deprecate In methods

[daedalus28]

Using _ as a placeholder obviates the need for the In method conversions, because they only save a single character at the cost of new things to learn:

F.someMethodIn(x) vs
_.someMethod(_, x)

Additionally, sometimes our conversion methods would be useful together, e.g. an In and an On. A good example is unset - you might want to unset both in and on an object, and defining compound conversion conventions seems messy (unsetIon?).

In order to make this work, we either need to explicitly curry all our conversions, or wait for lodash/lodash#3440 to be fixed

[daedalus28]

lodash/lodash#3440 is fixed 😄