go/neo/proto: protogen: Fix naming thinko in decoderN.genBuf

For decode-family of functions protogen.go sticks to convention to name
target variable to where to assign the result as "assignto", not "path".

No change in generated code.

go/neo/proto/protogen.go

@@ -961,7 +961,7 @@ func (e *encoderN) genBuf(path string) {
 	e.genSlice1(path+".XData()", nil /* typ unused */)
 }
 
-func (d *decoderN) genBuf(path string) {
+func (d *decoderN) genBuf(assignto string) {
 	d.emit("{")
 	d.genBasic("l:", types.Typ[types.Uint32], nil)
 
@@ -971,8 +971,8 @@ func (d *decoderN) genBuf(path string) {
 	d.overflow.AddExpr("uint64(l)")
 
 	// TODO eventually do not copy but reference original
-	d.emit("%v= mem.BufAlloc(int(l))", path)
-	d.emit("copy(%v.Data, data[:l])", path)
+	d.emit("%v= mem.BufAlloc(int(l))", assignto)
+	d.emit("copy(%v.Data, data[:l])", assignto)
 
 	d.emit("data = data[l:]")
 	d.emit("}")