Re-translate the Japanese version (#1871)

* Retranslate Japanese docs with GPT-5.4

* Retranslate Japanese code with GPT-5.4

ja/codes/go/chapter_greedy/fractional_knapsack_test.go

@@ -0,0 +1,20 @@
+// File: fractional_knapsack_test.go
+// Created Time: 2023-07-23
+// Author: Reanon (793584285@qq.com)
+
+package chapter_greedy
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestFractionalKnapsack(t *testing.T) {
+	wgt := []int{10, 20, 30, 40, 50}
+	val := []int{50, 120, 150, 210, 240}
+	capacity := 50
+
+	// 貪欲法
+	res := fractionalKnapsack(wgt, val, capacity)
+	fmt.Println("ナップサック容量を超えない最大価値は", res)
+}