The mix release does not copy include folders

[x0id]

Elixir and Erlang/OTP versions

$ elixir --version
Erlang/OTP 26 [erts-14.0.2] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit:ns] [dtrace]

Elixir 1.15.7 (compiled with Erlang/OTP 26)

Operating system

any

Current behavior

The "mix help release" clearly states the target app structure contains "include" folders, but the actual release assemble code doesn't copy it. This line in the code https://github.com/elixir-lang/elixir/blame/7d04c40fc09696f0180baef6b088da87234afd0c/lib/mix/lib/mix/release.ex#L71 shows that only "priv" dirs are copied.
Having "include" in the release is important for troubleshooting issues when we need to import records defined in header files, for example.

Expected behavior

The mix release is expected to copy applications' include folders as per the documentation.