Fix abstract def parameter name in LibEvent::EventLoop#send_to

[straight-shoota]

Fixup for #14643

[ysbaddaden]

I believe the other implementations are also affected:

src/crystal/system/wasi/event_loop.cr
55:  def send_to(socket : ::Socket, slice : Bytes, addr : ::Socket::Address) : Int32

src/crystal/system/win32/event_loop_iocp.cr
182:  def send_to(socket : ::Socket, bytes : Bytes, addr : ::Socket::Address) : Int32

[ysbaddaden]

And now it complains about the bytes param on Windows 😩