[3pt] fiber.wakeup() in Lua and fiber_wakeup() in C are nop on self

[TarantoolBot]

Since: Tarantool 2.7.2
SME: @Gerold103
root document: https://www.tarantool.io/ru/doc/latest/dev_guide/reference_capi/fiber/#c.fiber_wakeup

Details

In Lua fiber.wakeup() being called on the current fiber does not
do anything, safe to use. The same for fiber_wakeup() in C.

tarantool/tarantool@db0ded5.

Note: fiber.wakeup() is not described. Why?