fix: reintroduce BitReverse in fft package as deprecated for backward… (#740)

Author: gbotrel

ecc/bls12-377/fr/fft/domain.go

@@ -10,6 +10,7 @@ import (
 	"{{ .FieldPackagePath }}"
 
 	"github.com/consensys/gnark-crypto/ecc"
+	"github.com/consensys/gnark-crypto/utils"
 )
 
 // Domain with a power of 2 cardinality
@@ -310,3 +311,13 @@ func (d *Domain) ReadFrom(r io.Reader) (int64, error) {
 
 	return read, nil
 }
+
+
+// BitReverse applies the bit-reversal permutation to v.
+//
+// The length of v must be a power of 2.
+//
+// Deprecated: Use [utils.BitReverse] instead.
+func BitReverse(v []{{ .FF }}.Element) {
+	utils.BitReverse(v)
+}