added surface area calc for pyramid

[Marko411]

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

I added the following function for calculating the area of a pyramid in the area calculation methods part of the code

/**

• Calculate the surface area of a pyramid with a square base.
• @param sideLength side length of the square base
• @param slantHeight slant height of the pyramid
• @return surface area of the given pyramid
  */
  public static double surfaceAreaPyramid(final double sideLength, final double slantHeight) {
  if (sideLength <= 0) {
  throw new IllegalArgumentException("Must be a positive sideLength");
  }
  if (slantHeight <= 0) {
  throw new IllegalArgumentException("Must be a positive slantHeight");
  }
  double baseArea = sideLength * sideLength;
  double lateralSurfaceArea = 2 * sideLength * slantHeight;
  return baseArea + lateralSurfaceArea;
  }

[Marko411]

I want to add a comment on line 198

[Marko411]

my review is done

[DenizAltunkapan]

solved in #6853