Some matcher structs (Number, DateTime) have InRange method that checks that the value belongs to given range [min; max].

Another convenient thing would be InList method, that checks that the value equals to one of the given values a, b, c, ....

For example:

array.Element(1).String().InList("green", "red")

We need to add InList and counterpart NotInList methods to the following structs:

• Value
• Object
• Array
• String
• Number
• Boolean (just for completeness)
• Duration
• DateTime

The new methods can use assertions of type AssertBelongs and AssertNotBelongs. Please place these methods after InRange, or after Equal* if there is no InRange for this struct.

Each method should have documentation comment with code example and be covered by a unit test. It would be also nice to demonstrate usage of InRange and InList in _examples/fruits_test.go.