fix spacing in doc string

Author: pazzo83

src/bagofwords_transformer.jl

@@ -1,12 +1,14 @@
 """
     BagOfWordsTransformer()
+
 Convert a collection of raw documents to matrix representing a bag-of-words structure.
 Essentially, a bag-of-words approach to representing documents in a matrix is comprised of
 a count of every word in the document corpus/collection for every document. This is a simple
 but often quite powerful way of representing documents as vectors. The resulting representation is
 a matrix with rows representing every document in the corpus and columns representing every word
 in the corpus. The value for each cell is the raw count of a particular word in a particular
 document.
+
 Similarly to the `TfidfTransformer`, the vocabulary considered can be restricted
 to words occuring in a maximum or minimum portion of documents.
 The parameters `max_doc_freq` and `min_doc_freq` restrict the vocabulary