Update datasets task tags to align tags with models (#4067)

* update tasks list

* update tags in dataset cards

* more cards updates

* update dataset tags parser

* fix multi-choice-qa

* style

* small improvements in some dataset cards

* allow certain tag fields to be empty

* update vision datasets tags

* use multi-class-image-classification and remove other tags

Commit from https://github.com/huggingface/datasets/commit/edb4411d4e884690b8b328dba4360dbda6b3cbc8

README.md

@@ -35,7 +35,7 @@ task_categories:
   sst2:
   - text-classification
   stsb:
-  - text-scoring
+  - text-classification
   wnli:
   - text-classification
 task_ids:
@@ -60,6 +60,7 @@ task_ids:
   sst2:
   - sentiment-classification
   stsb:
+  - text-scoring
   - semantic-similarity-scoring
   wnli:
   - text-classification-other-coreference-nli