Properly install Pattern library for documentation build (#2626)
Properly install Pattern library for documentation build (#2626)

* Probably fixes #2534

* Uppercase P

* Added comment

RaRe-Technologies/gensim,RaRe-Technologies/gensim,piskvorky/gensim,piskvorky/gensim,RaRe-Technologies/gensim,gojomo/gensim,gojomo/gensim,gojomo/gensim,piskvorky/gensim,gojomo/gensim,RaRe-Technologies/gensim