docs: Add comparison of toString(), printf(), and custom printDetails() usage

WHAT the file contains:
- A comparison table outlining three different approaches for object display in Java:
  1. **toString()**
  2. **printf()**
  3. **printDetails()**
- Each row lists pros and recommended usage scenarios.

WHY this matters:
- Helps decide the best method for printing/debugging object information.
- Provides clarity between reusable overrides (`toString()`), formatting needs (`printf()`), and explicit helper methods (`printDetails()`).
- Useful as a quick reference for beginners learning object display strategies.

HOW it is structured:
1. Markdown table with three columns:
   - **Method** → name of the approach.
   - **Pros** → advantages of each method.
   - **When to Use** → suggested scenarios for applying them.
2. Highlights `toString()` as the **best general practice** due to reusability.

Tips & gotchas:
- Overriding `toString()` is standard, but avoid exposing sensitive data in its output.
- `printf()` requires format specifiers (`%s`, `%d`, etc.) and works best for tabular or aligned output.
- `printDetails()` (custom void method) is clear but less reusable than `toString()`.

Use-cases:
- Documentation for Java beginners deciding how to output object state.
- Quick guide for interview preparation or coding best practices.
- Can be included in project guidelines to standardize debugging practices.

Short key: docs-object-display-methods-comparison.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan