Now that random generation is user-exposed, have better exception for invalid sites

Author: RudyTheDev

SharpVoronoiLib/Exceptions/VoronoiRandomPointGenerationEncounteredTooManyInvalidSites.cs

@@ -0,0 +1,5 @@
+namespace SharpVoronoiLib.Exceptions;
+
+public class VoronoiRandomPointGenerationEncounteredTooManyInvalidSites() 
+    : NullReferenceException("While generating random points for sites, the algorithm encountered too many invalid site points. " +
+                             "This is likely an issue with the random point generation algorithm.");

SharpVoronoiLib/Point Generation/RandomPointGeneration.cs

@@ -1,4 +1,6 @@
-namespace SharpVoronoiLib;
+using SharpVoronoiLib.Exceptions;
+
+namespace SharpVoronoiLib;
 
 internal abstract class RandomPointGeneration : IPointGenerationAlgorithm
 {
@@ -28,14 +30,14 @@ public List<VoronoiSite> Generate(double minX, double minY, double maxX, double
             {
                 i--;
                 failSafetyCounter--;
-                if (failSafetyCounter == 0) throw new Exception("Too many invalid points generated");
+                if (failSafetyCounter == 0) throw new VoronoiRandomPointGenerationEncounteredTooManyInvalidSites();
                 continue;
             }
 
             if (!sites.Add(site))
             {
                 failSafetyCounter--;
-                if (failSafetyCounter == 0) throw new Exception("Too many invalid points generated");
+                if (failSafetyCounter == 0) throw new VoronoiRandomPointGenerationEncounteredTooManyInvalidSites();
                 i--;
             }
         }