remove `matrix`

[terasakisatoshi]

This PR resolves #1

julia> tokenize(Tokenizer(), "アイス")
1-element Vector{Tuple{String, String}}:
 ("アイス", "名詞,一般,*,*,*,*,アイス,アイス,アイス")

julia> tokenize(Tokenizer(), "不思議の国のアリス")
5-element Vector{Tuple{String, String}}:
 ("不思議", "名詞,形容動詞語幹,*,*,*,*,不思議,フシギ,フシギ")
 ("の", "助詞,連体化,*,*,*,*,の,ノ,ノ")
 ("国", "名詞,一般,*,*,*,*,国,クニ,クニ")
 ("の", "助詞,連体化,*,*,*,*,の,ノ,ノ")
 ("アリス", "名詞,固有名詞,人名,名,*,*,アリス,アリス,アリス")

julia> tokenize(Tokenizer(), "すもももももももものうち")
7-element Vector{Tuple{String, String}}:
 ("すもも", "名詞,一般,*,*,*,*,すもも,スモモ,スモモ")
 ("も", "助詞,係助詞,*,*,*,*,も,モ,モ")
 ("もも", "名詞,一般,*,*,*,*,もも,モモ,モモ")
 ("も", "助詞,係助詞,*,*,*,*,も,モ,モ")
 ("もも", "名詞,一般,*,*,*,*,もも,モモ,モモ")
 ("の", "助詞,連体化,*,*,*,*,の,ノ,ノ")
 ("うち", "名詞,非自立,副詞可能,*,*,*,うち,ウチ,ウチ")

julia>

[nakagami]

Thanks