style: format code with Gofumpt

This commit fixes the style issues introduced in 6e234a2 according to the output
from Gofumpt.

Details: #21

quic_clienthello_reconstructor.go

@@ -28,8 +28,10 @@ var (
 	ErrNeedMoreFrames    = errors.New("need more CRYPTO frames")
 )
 
-const maxCRYPTOFragments = 32
-const maxCRYPTOLength = 0x10000 // 10KiB
+const (
+	maxCRYPTOFragments = 32
+	maxCRYPTOLength    = 0x10000 // 10KiB
+)
 
 // AddCRYPTOFragment adds a CRYPTO frame fragment to the reconstructor.
 // By default, all fragments are saved into an internal map as a pending

quic_frame.go

@@ -212,6 +212,8 @@ func (f *CRYPTO) Data() []byte {
 type Frame = QUICFrame
 
 // type guards:
-var _ QUICFrame = (*PADDING)(nil)
-var _ QUICFrame = (*PING)(nil)
-var _ QUICFrame = (*CRYPTO)(nil)
+var (
+	_ QUICFrame = (*PADDING)(nil)
+	_ QUICFrame = (*PING)(nil)
+	_ QUICFrame = (*CRYPTO)(nil)
+)