message: change [[nodiscard]] to FOLLY_NODISCARD for "fbcode/quic/codec/QuicPacketBuilder.h"
  Summary:
  ovrsource is not happy about [[nodiscard]] when sync:
  use FOLLY_NODISCARD instead
diff: @@ -323,7 +323,7 @@ class InplaceSizeEnforcedPacketBuilder : public WrapperPacketBuilderInterface {
  * packet size + cipher oveahead and that iobuf has enough tailroom,
  * otherwise false
  */
  - [[nodiscard]] bool canBuildPacket() const noexcept override;
  + FOLLY_NODISCARD bool canBuildPacket() const noexcept override;
  Packet buildPacket() && override;
  @@ -352,12 +352,12 @@ class VersionNegotiationPacketBuilder {
  * Whether the packet builder is able to build a packet. This should be
  * checked right after the creation of a packet builder object.
  */
  - [[nodiscard]] bool canBuildPacket() const noexcept;
  + FOLLY_NODISCARD bool canBuildPacket() const noexcept;
  private:
  void writeVersionNegotiationPacket(const std::vector<QuicVersion>& versions);
  - [[nodiscard]] uint8_t generateRandomPacketType() const;
  + FOLLY_NODISCARD uint8_t generateRandomPacketType() const;
  private:
  uint32_t remainingBytes_;
  