Fix doc2vec documentation
Fix doc2vec documentation

Fixed descriptions of various arguments passed up to parent Word2Vec __init__ method.
RaRe-Technologies/gensim,gojomo/gensim,piskvorky/gensim,markroxor/gensim,macks22/gensim,gojomo/gensim,gojomo/gensim,piskvorky/gensim,summanlp/gensim,RaRe-Technologies/gensim,markroxor/gensim,macks22/gensim,gojomo/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim,piskvorky/gensim,summanlp/gensim,macks22/gensim,mattilyra/gensim,markroxor/gensim,ELind77/gensim,robotcator/gensim,robotcator/gensim,ELind77/gensim,mattilyra/gensim,robotcator/gensim,mattilyra/gensim,summanlp/gensim,ELind77/gensim