Added example and Unit tests for ClampToZero method on p5.Vector.

[Forchapeatl]

Resolves #6750

Changes:

Screenshots of the change:

PR Checklist

• [x] npm run lint passes
• [x] Inline documentation is included / updated
• [x] Unit tests are included / updated

[Forchapeatl]

Than you for the review @ashish1729 . I have made the updated changes, please have a look at my PR.

[ashish1729]

thank you for fixing all these, although I am not a maintainer, I don't think I can/should approve changes.

[Forchapeatl]

No worries @ashish1729 , I really needed someone to put me on track. Thank you.

[perminder-17]

Keep up the great work. Some thoughts, let me know what you feel. :)

Here how it shows when you run grunt yui:dev in your code-editor, you need to open the developer tools in your browser to see the log values.

This could be resolved by two solution.

1. If you write the code just as a function, for ex:

```js
your sketch....```

and by writing some description for eg; Here's the after result (maybe in your words):

```js
before : values
after : values```

2. The second option is to use text() function and can write the log values into the canvas by making a canvas of 100X100.

Let me know what you think by these thoughts :)

[Forchapeatl]

thanks @perminder-17 , I will work on this over the weekend