Add `language_bcp47` tag (#4753)

* fix ms_terms

* fix ted_talks_iwslt

* move tags to language_bcp47

* fix bad codes

* add language_details and language_bcp47 in DatasetMetadata

* more fixes

* fix wiki_dpr

Commit from https://github.com/huggingface/datasets/commit/aa48a29d1304167dff37cef0ed7542f29376ee2d

README.md

@@ -5,15 +5,15 @@ annotations_creators:
 language_creators:
 - crowdsourced
 language:
-- en
 - ar
 - bn
+- en
 - fi
 - id
 - ja
-- sw
 - ko
 - ru
+- sw
 - te
 - th
 license: