PSA: "_llcpp" binding suffix in GN and "lib/fidl/llcpp" includes are going away

[Yifei Teng]

You may stop reading if you don't write C++ or don't use the LLCPP bindings. Re New C++ FIDL bindings are here (an update on LLCPP), we're dropping the "LL" (low-level) from the binding's name. I'm landing two CLs:

- fxrev.dev/710384 which moves headers includes from "#include <lib/fidl/llcpp/...>" to "#include <lib/fidl/cpp/wire/...>"

- fxrev.dev/710563 which renames generated bindings code GN targets from "fuchsia.my.lib_llcpp" to "fuchsia.my.lib_cpp_wire".

If you have in-flight CLs that use the older names, you may follow similar changes in those two CLs to update them to new names. Or reach out to yif...@google.com if you need more help. Thanks!