Fix hashtag plugin: add support for full width middle dot ・

[yuiseki]

Nice to meet you, Thank you for the great OSS you are providing!
I love to using this OSS!

There is one problem in hashtag plugin with Japanese that I would like to fix, and I am sending this pull request.

Issue

• linkifyjs hashtag plugin cannot parse full width middle dot ・ correctly
• Full width middle dot ・ is a very important symbol in Japanese
  • That is used in many cases in Japanese
    • Name of person
    • Title of the work
    • Name of a sports team
    • Name of brand
• X (formerly Twitter) supports full width middle dot in hashtags

Examples

• #アラン・チューリング
  • Alan Mathison Turing
• #スター・ウォーズ
  • STAR WARS
• #レアル・マドリード
  • Real Madrid CF
• #コカ・コーラ
  • coca cola

How to fix

• I've added FULLWIDTHMIDDLEDOT to
  • packages/linkifyjs/src/text.js
  • packages/linkifyjs/src/scanner.js
• I've updated packages/linkify-plugin-hashtag/src/hashtag.js
• I've added test cases to
  • test/spec/linkifyjs/scanner.test.js
  • test/spec/linkify-plugin-hashtag.test.js

What I've checked

• npm run build
• npm run lint
• npm run test

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I would be very grateful if this issue could be fixed.
I would appreciate your consideration of merge this pull request.

[nfrasser]

Hi @yuiseki, this looks great, thank you very much for your contribution!

[coveralls]

Pull Request Test Coverage Report for Build 11434698969

Details

• 7 of 7 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 95.925%

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Totals
Change from base Build 6952525806:	0.01%
Covered Lines:	1097
Relevant Lines:	1118

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💛 - Coveralls