text: Title: Fix documentation link to mycorpus.txt download
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  #### Problem description
  
  Trying to reproduce Corpora and Vector Space tutorial given in the documentation, but the link to download txt file is not working. The link given in the tutorial [here](https://radimrehurek.com/gensim/auto_examples/core/run_corpora_and_vector_spaces.html#corpus-streaming-one-document-at-a-time) is giving 404 error.
  
  #### Steps/code/corpus to reproduce
  
  Just visit this [link](https://radimrehurek.com/gensim/mycorpus.txt) which is used in the code given in the documentation, it is not working.
  