[spec] `let` ported from `test.check/let` to `clojure.spec.gen`

Description

When using `clojure.spec` for elaborate specifications and `clojure.spec.gen` for generative testing, developers often find themselves writing code which heavily relies on `clojure.spec.gen/fmap`. This is sometimes unnatural and difficult to read.

To make writing custom generators easier, this patch ports `test.check/let` to `clojure.spec.gen`. Now developers can write generators more simply.

Environment

None

Assignee

Unassigned

Reporter

import

Labels

Approval

None

Patch

Code and Test

Affects versions

Priority

Minor
Configure