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

@@ -9,7 +9,6 @@ task_ids:
 - language-modeling
 - masked-language-modeling
 language:
-- 'no'
 - af
 - am
 - an
@@ -74,6 +73,7 @@ language:
 - ne
 - nl
 - nn
+- 'no'
 - oc
 - or
 - pa