Retranslate the complete English edition from Simplified Chinese (#2010)

* Retranslate the complete English edition from Simplified Chinese

* Polish three English explanations after reader-focused review

en/codes/java/chapter_searching/linear_search.java

@@ -11,13 +11,13 @@ import utils.*;
 public class linear_search {
     /* Linear search (array) */
     static int linearSearchArray(int[] nums, int target) {
-        // Traverse array
+        // Traverse the array
         for (int i = 0; i < nums.length; i++) {
-            // Found the target element, return its index
+            // The target element was found; return its index
             if (nums[i] == target)
                 return i;
         }
-        // Target element not found, return -1
+        // The target element was not found; return -1
         return -1;
     }
 
@@ -25,26 +25,26 @@ public class linear_search {
     static ListNode linearSearchLinkedList(ListNode head, int target) {
         // Traverse the linked list
         while (head != null) {
-            // Found the target node, return it
+            // The target node was found; return it
             if (head.val == target)
                 return head;
             head = head.next;
         }
-        // Target node not found, return null
+        // The target node was not found; return null
         return null;
     }
 
     public static void main(String[] args) {
         int target = 3;
 
-        /* Perform linear search in array */
+        /* Perform linear search on the array */
         int[] nums = { 1, 5, 3, 2, 4, 7, 5, 9, 10, 8 };
         int index = linearSearchArray(nums, target);
         System.out.println("Index of target element 3 = " + index);
 
-        /* Perform linear search in linked list */
+        /* Perform linear search on the linked list */
         ListNode head = ListNode.arrToLinkedList(nums);
         ListNode node = linearSearchLinkedList(head, target);
-        System.out.println("Node object corresponding to target node value 3 is " + node);
+        System.out.println("The node object corresponding to target value 3 is " + node);
     }
 }