message: Improve ResourcePool::capacity() readability
diff: #include "Constants.h"
  +#include <algorithm>
  #include <iostream>
  using namespace NAS2D::Xml;
  @@ -323,11 +324,7 @@ void ResourcePool::pullResources(ResourcePool& resourcePool)
  */
  void ResourcePool::capacity(int newCapacity)
  {
  - mCapacity = newCapacity;
  -
  - // Prevent negative values.
  - if (newCapacity < 0)
  - mCapacity = 0;
  + mCapacity = std::clamp(newCapacity, 0, INT32_MAX);
  }
  