Fix JavaDoc inaccuracies and missing documentation

[Copilot]

JavaDoc comments contained outdated descriptions and range documentation that didn't match actual code behavior.

Changes

• CheckGuess: Corrected valid range from (1-100) to (1-101) to match actual implementation
• RandomNumber: Clarified range notation from ambiguous "between 0 and max" to explicit "[0, max]" with inclusive bounds
• ReadVersionFile: Removed stale "placeholder version" reference; updated to "fallback version"
• HighScore: Added missing JavaDoc for toString() override

Example

// Before
/**
 * Validates that a guess is within the acceptable range (1-100).
 * @throws IllegalArgumentException if the guess is less than 1 or greater than 101
 */
void check(int guess) {
    if (guess < 1 || guess > 101) { // Actually accepts 1-101
        throw new IllegalArgumentException("Invalid number!");
    }
}

// After
/**
 * Validates that a guess is within the acceptable range (1-101).
 * @throws IllegalArgumentException if the guess is less than 1 or greater than 101
 */

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Review JavaDoc</issue_title>
<issue_description>Make sure it is all up to date and organized </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Review JavaDoc #85

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.