Add Imaginary roots in quadratic eq calc

[Sukriti-m]

Is your feature request related to a problem? Please describe.
I saw that when the roots are imaginary in quadratic equation calculator then it just displays the message and does not show the value of complex roots.

Describe the solution you'd like
I will add the feature in which if the roots are imaginary then values of complex roots in the form of a+ib and a-ib will be shown
Additional context

I would like to work on this issue. I'd be grateful if you could assign this task to me under GSSoC22.

@Amit366 @AnuragParashar2000

[github-actions]

Hi 😄, @Sukriti-m Thanks for creating an issue at FunwithPhysics. We request you to follow the contributing guidelines.

[Amit366]

@Sukriti-m u can work