POS Filter: Allow forward matching

[sorami]

The sudachi_part_of_speech filter excludes the words with specified POS information.

Sudachi POS information is a list, consisting 6 items; Currently, a user can specify either

• 1st-4th items together (excluding asterisk items)
• 5th item (活用型)
• 6th item (活用形)
  to filter out the result.

Currently, the user needs to specify the entire POS information.

It would be convenient if a user can just write part of the POS (say, first 1 or 2 items of the POS information list), and the filtering is done by forward matching.

Thanks to @cidrugHug8 for mentioning the topic in Elasticsearchのための新しい形態素解析器 「Sudachi」 - Qiita (in Japanese).

[sorami]

Merged #22.

Forward matching for POS [0-4], [4, 6], and [5].

So now you can write in any of these forms;

• 1 - e.g., 名詞
• 1,2 - e.g., 名詞,固有名詞
• 1,2,3 - e.g., 名詞,固有名詞,地名
• 1,2,3,4 - e.g., 名詞,固有名詞,地名,一般
• 5 - e.g., 五段-カ行
• 6 - e.g., 終止形-一般
• 5,6 - e.g., 五段-カ行,終止形-一般