(Mitchell's already on vacation) Both fidl-format sdk/fidl/fuchsia.net.dhcpv6/server.fidl and fx format-code --files=sdk/fidl/fuchsia.net.dhcpv6/server.fidl seem to leave that string alone. I guess it got fixed at some point?
fidl-format sdk/fidl/fuchsia.net.dhcpv6/server.fidl
fx format-code --files=sdk/fidl/fuchsia.net.dhcpv6/server.fidl