Update 016-creating-an-interactive-menu-in-bash.md

[prathamkankheria]

I updated this line *) echo -e "${red}Wrong option.${clear}"; menu ;; and red variable was not defined so i added it

[what-the-diff]

PR Summary

• Introduction of a new color variable
  A new variable red has been included to represent the color red in the system.

• Redefinition of error messaging
  The update includes changes to print error messages with consistent color formatting. Now, the red variable is used in echo commands to indicate incorrect options.

• Stricter adherence to string formatting conventions
  Adhering to best practices, now all the text messages in echo commands will be surrounded by double quotes. This change ensures correct and expected handling of these messages in the code.

[bobbyiliev]

Nice! Thanks!