Foundations: Calculator: Reword calculator display reqirements

[JoshDevHub]

Because

The previous wording makes it seem as if the program data should be pulled from the DOM. This is almost always a bad idea. And while I'm not overly concerned with learners following best practices (especially at this stage of the curriculum), I also don't think the curriculum should be actively telling them to do something like this.

This PR

• Updates the wording on the calculator display requirement to write functions that update the number data as the user clicks buttons on the calculator. The display should then update to reflect the number's value.

Issue

Closes #XXXXX

Additional Information

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