fi-0180: Zircon C types are experimental {:#fi-0180}

Experimental: Zircon C types are an unstable feature gated behind the --experimental zx_c_types fidlc flag.

The built-in types usize, uintptr, uchar, and experimental_pointer are being developed for the Zither project. They cannot be used in ordinary FIDL libraries:

{% include “docs/reference/fidl/language/error-catalog/label/_bad.md” %}

{% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="tools/fidl/fidlc/tests/fidl/bad/fi-0180.test.fidl" exclude_regexp="\/\/ (Copyright 20|Use of|found in).*" %}

Instead, use a different type, for example uint64 instead of usize:

{% include “docs/reference/fidl/language/error-catalog/label/_good.md” %}

{% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="tools/fidl/fidlc/tests/fidl/good/fi-0180.test.fidl" exclude_regexp="\/\/ (Copyright 20|Use of|found in).*" %}