Add multiline-loop to complement multiline-if-else

[hanggrian]

Description

Related to #2223.

Added MultiLineLoopRule that, like MultiLineIfElseRule, checks violation in for, while, and do statements.

Checklist

Before submitting the PR, please check following (checks which are not relevant may be ignored):

• Commit message are well written. In addition to a short title, the commit message also explain why a change is made.
• At least one commit message contains a reference Closes #<xxx> or Fixes #<xxx> (replace<xxx> with issue number)
• Tests are added
• KtLint format has been applied on source code itself and violations are fixed
• CHANGELOG.md is updated
• PR description added

Documentation is updated. See difference between snapshot and release documentation

• Snapshot documentation in case documentation is to be released together with a code change
• Release documentation in case documentation is related to a released version of ktlint and has to be published as soon as the change is merged to master
• In case of adding a new rule, it needs to be added to experimental rules documentation

[paul-dingemans]

Tnx for your contribution. I will have a look after 1.0.1 is released. Functional change like a new rule have to wait to next minor release.

[hanggrian]

Hi Paul. I understand, thanks for your response. And also for pointing out the bracing difference between Kotlin and Android style guides.

[paul-dingemans]

Well done! I see that you picked up quite some conventions of the project. Please address the remarks.

[paul-dingemans]

According to Android style guide:

Braces are otherwise required for any if, for, when branch, do, and while statements and expressions, even when the body is empty or contains only a single statement.

Kotlin style guide does not mention it explicitly, but I am fine with imposing this on code styles.