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

@@ -14,9 +14,9 @@ size_categories:
 source_datasets:
 - original
 task_categories:
-- conditional-text-generation
+- text2text-generation
 task_ids:
-- conditional-text-generation-other-debugging
+- text2text-generation-other-debugging
 pretty_name: CodeXGlueCcCodeRefinement
 ---
 
@@ -58,7 +58,7 @@ We use the dataset released by this paper(https://arxiv.org/pdf/1812.08693.pdf).
 
 ### Supported Tasks and Leaderboards
 
-- `conditional-text-generation-other-debugging`: The dataset can be used to train a model for automatically fixing buggy code.
+- `text2text-generation-other-debugging`: The dataset can be used to train a model for automatically fixing buggy code.
 
 ### Languages