Reworked diagnostics, saves line positions in memory, instead of calculating later.

Upsilon/BaseTypes/ScriptFunction/ScriptMethodInfoFunction.cs

@@ -107,11 +107,9 @@ namespace Upsilon.BaseTypes.ScriptFunction
                     // if we haven't found a method, we throw an exception
                     if (method == null)
                     {
-                        var (i, pos) = diagnostics.ScriptString.GetLinePosition(span.Start);
-                        var line = diagnostics.ScriptString.GetLine(i);
                         throw new ScriptRuntimeException(
                             $"Can't find method {_method.Name} with parameter types {string.Join(", ", convertedTypes.Select(x => x.Name))} on type {_object.GetType().Name}",
-                            i, pos, line);
+                            span, diagnostics.ScriptString.GetSpan(span));
                     }
                     // get the method parameters
                     var parameters = method.GetParameters();