Match ktlint_code_style with Ktlint documentation

[Jaehwa-Noh]

Ktlint document says that

Starting from version 1.0, ktlint_official is the default code style. If you want to revert to another code style, then set the .editorconfig property ktlint_code_style.

But Spotless default set intellij_idea It makes developer mistake and misconception.

According Ktlint documentation, only one want to revert another code style must set the ktlint_code_style, but in Spotless need to set the ktlint_code_style who want to apply ktlint_official or else styles.

[nedtwigg]

• This needs changelog entries in CHANGES.md, plugin-gradle/CHANGES.md, and plugin-maven/CHANGES.md
• These entries need to look like this:

- **BREAKING** default `ktlint` editorconfig `ktlint_code_style` changed from `intellij_idea` to `ktlint_official` to better match the ktlint docs. ([#2090](https://github.com/diffplug/spotless/pull/2090))
  - to keep the previous behavior of `intellij_idea`, you must do "blah"

[Goooler]

Actually, the context was #1808 (comment).

[Goooler]

Maybe we can just note the default style intellij_idea in ktlint sections in docs, users can override them anyway in their configs.

[Jaehwa-Noh]

Yes, developer can override the style.
But the problem is that I introduced.

According Ktlint documentation, only one want to revert another code style must set the ktlint_code_style, but in Spotless need to set the ktlint_code_style who want to apply ktlint_official or else styles.

Unmatched default with ktlint documentation, makes developer mistake and misconception.

[Goooler]

That's the ktlint CLI's default value instead of this plugin.

Did you see the context above? This change will break users' compatibility, it's so painful and annoying.

[Jaehwa-Noh]

No, I don't think that break users' compatibility.
This ktlint_official is ktlint's default value, and spotless loads ktlint plugin, so that there's no reason doesn't follow ktlint official documentation.

See below snippet

spotless {
  kotlin {
    ktlint()
  }
}

You say that spotless will apply intellij_idea style ktlint.
But the one who read ktlint documentation, will say that spotless will apply ktlint_official style ktlint.
This inconsistent situation will bring more fatigue to developer. Every developers must double check both spotless documentation and ktlint documentation what is different.
It is non-sense.

[Jaehwa-Noh]

I add the instruction in CHANGES.md.
The test, however, failed because of default ktlint style changed. so that I need to adjust the test.
I am now changing this draft to solve the test problem.

[Goooler]

What you actually need to do is reverting 7de7991, but anyway I don't wanna do this breaking now. Docs will be updated in #2092, new users will see it.

[Jaehwa-Noh]

Okay, I got it.