docs: fix import and usage of French NER dataset

The `WIKINER_FRENCH` name is deprecated and `NER_MULTI_WIKINER` should be used instead.

README.md

@@ -74,11 +74,11 @@ The following Flair script was used to train this model:
 
 ```python
 from flair.data import Corpus
-from flair.datasets import WIKINER_FRENCH
+from flair.datasets import NER_MULTI_WIKINER
 from flair.embeddings import WordEmbeddings, StackedEmbeddings, FlairEmbeddings
 
 # 1. get the corpus
-corpus: Corpus = WIKINER_FRENCH()
+corpus: Corpus = NER_MULTI_WIKINER(languages="fr")
 
 # 2. what tag do we want to predict?
 tag_type = 'ner'