Add task category, link to paper

This PR ensures the dataset can be found at https://huggingface.co/papers/2505.20650 and https://huggingface.co/datasets?task_categories=task_categories:table-question-answering.

README.md

@@ -1,4 +1,8 @@
 ---
+task_categories:
+- table-question-answering
+license: apache-2.0
+library_name: datasets
 dataset_info:
   features:
   - name: context
@@ -25,3 +29,5 @@ configs:
   - split: test
     path: data/test-*
 ---
+
+This dataset is from the paper [FinTagging: An LLM-ready Benchmark for Extracting and Structuring Financial Information](https://huggingface.co/papers/2505.20650).