fi-0185: Unicode escape sequence missing braces {:#fi-0185}

Unicode escape sequences in string literals must specify a code point in braces:

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

{% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="tools/fidl/fidlc/tests/fidl/bad/fi-0185.test.fidl" exclude_regexp="\/\/ (Copyright 20|Use of|found in).*" %}

To fix the error, specify a code point in braces:

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

{% includecode gerrit_repo="fuchsia/fuchsia" gerrit_path="tools/fidl/fidlc/tests/fidl/good/fi-0185.test.fidl" exclude_regexp="\/\/ (Copyright 20|Use of|found in).*" %}