improve toString of VariationDiffSources

Author: pmbittner

src/main/java/org/variantsync/diffdetective/variation/diff/source/PatchString.java

@@ -6,4 +6,9 @@
  * Source for VariationDiffs that were created from a patch given as a String.
  * @param getDiff The patch as a String.
  */
-public record PatchString(String getDiff) implements TextBasedDiff, VariationDiffSource { }
+public record PatchString(String getDiff) implements TextBasedDiff, VariationDiffSource {
+    @Override
+    public String toString() {
+        return "from line-based diff " + getDiff;
+    }
+}

src/main/java/org/variantsync/diffdetective/variation/diff/source/VariationTreeDiffSource.java

@@ -11,4 +11,8 @@ public record VariationTreeDiffSource(
     VariationTreeSource before,
     VariationTreeSource after
 ) implements VariationDiffSource {
+    @Override
+    public String toString() {
+        return "from trees [" + before + "] and [" + after + "]";
+    }
 }