…s, footer, icons, and button components

…cross various Java programming topics

- Added spacing and formatting improvements in static keyword, switch statement, this keyword, and variable documentation.
- Enhanced explanations and examples in while and do-while loop sections.
- Updated program descriptions for better readability in add-two-integers, calculate-compound-interest, calculate-power-of-a-number, and other program files.
- Corrected minor grammatical errors and improved phrasing in multiple program files.
- Ensured consistent output formatting and added missing output sections in several examples.