project_calculator: Removed the "make it look nice" text.

[fullstackjunkie]

I removed the make it look nice line, so people do not spend more time trying to make it look nice, or more than they normally would.

Because

I removed the make it look nice so people do not spend too much time on CSS.

This PR

I removed this line
-Make it look nice! This is a great project to practice your CSS skills. At least make the operations a different color from the keypad buttons.

Issue

Closes #XXXXX

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide