Include [Theory] data in xUnit test names

This fixes spekt/junit.testlogger#50 by including the xUnit theory data in test names.

src/TestLogger/Extensions/XunitTestAdapter.cs

@@ -46,6 +46,14 @@ public List<TestResultInfo> TransformResults(
                     result.Messages.Add(new TestResultMessage("skipReason", skipReason));
                 }
 
+                string displayName = result.Result.DisplayName;
+
+                // Add parameters for theories.
+                if (displayName.Contains("("))
+                {
+                    result.Method += displayName.Substring(displayName.IndexOf("("));
+                }
+
                 transformedResults.Add(result);
             }