custom warning message support

[azu]

  - expected: TechBooster
    pattern: tech
    prh: custom warning message

prh support prh field.
it is used for custom warning message.

[azu]

I think use message is better naming..

[azu]

We think about message format.

${actual} => ${expected}\n${prh}

thought?

[azu]

prh provide this as following

rule.raw.prh

[Leko]

${actual} => ${expected}\n${prh}

It would be nice.

[azu]

Release https://github.com/textlint-rule/textlint-rule-prh/releases/tag/5.2.0