docs: improve LinearSearch documentation with examples and step-by-step explanation (#7435)

Author: 07Vineet07

src/main/java/com/thealgorithms/searches/LinearSearch.java

@@ -10,10 +10,34 @@
  *
  * It works for both sorted and unsorted arrays.
  *
+ * <p>How it works step-by-step:
+ * <ol>
+ *   <li>Start from the first element of the array.</li>
+ *   <li>Compare the current element with the target value.</li>
+ *   <li>If they match, return the current index.</li>
+ *   <li>If they don't match, move to the next element.</li>
+ *   <li>Repeat until the element is found or the array ends.</li>
+ *   <li>If not found, return -1.</li>
+ * </ol>
+ *
+ * <p>Example:
+ * <pre>
+ *   Input array: [5, 3, 8, 1, 9]
+ *   Target: 8
+ *
+ *   Step 1: Compare 5 with 8 → no match, move on
+ *   Step 2: Compare 3 with 8 → no match, move on
+ *   Step 3: Compare 8 with 8 → match found at index 2!
+ *
+ *   Output: 2
+ *
+ *   If target = 7:
+ *   Output: -1 (not found)
+ * </pre>
  * Time Complexity:
- *  - Best case: O(1)
- *  - Average case: O(n)
- *  - Worst case: O(n)
+ *  - Best case: O(1) - target is the first element
+ *  - Average case: O(n) - target is somewhere in the middle
+ *  - Worst case: O(n) - target is last or not present
  *
  * Space Complexity: O(1)
  *
@@ -25,9 +49,10 @@
 public class LinearSearch implements SearchAlgorithm {
 
     /**
-     * Generic Linear search method
+     * Generic Linear search method that searches for a value
+     * in the given array by checking each element one by one.
      *
-     * @param array List to be searched
+     * @param array List to be searched (can be unsorted)
      * @param value Key being searched for
      * @return Location of the key, -1 if array is null or empty, or key not found
      */