feat: adds customGroup.newlinesInside option

[hugop95]

First PR aiming to partially resolve the issue #401.

• ⚙️ PR 1 (this): Add customGroup.newlinesInside option. We will take the opportunity to create a getNewlinesBetweenOption method that will help us later to precisely customize newline behavior between two specific groups.
• ❌ PR 2: Add a way to choose a specific newline behavior between two groups. See the proposals here.

Description

We currently have the newlinesBetween option, which applies the same newlines-related rules between all groups.
This PR adds a sub-option for the new array-based customGroups:

• newlinesInside?: 'always' | 'never'

Here is the list of rules with this new addition:

• sort-classes
• sort-modules
• sort-object-types
• sort-interfaces

New option

customGroup.newlinesInside?: 'ignore' | 'always' | 'never'

Newlines rule that should be applied between two consecutive nodes of the same custom group.

Example: Enforce a newline between all class methods.

{
  customGroups: [
    {
      groupName: "methodsWithNewlinesBetween",
      selector: "method",
      newlinesInside: "always"
    }
  ]
}

Other changes

• Unifies the way spacing errors are reported:
  • The leftNum < rightNum check is currently only made if numberOfEmptyLinesBetween === 0 (as confirmed by passing tests).
  • With newlinesBetween: always and if numberOfEmptyLinesBetween > 1, we were not checking if leftNum < rightNum.
  • The leftNum < rightNum check is not made when newlinesBetween: never either (as confirmed by passing tests).
  • => Always check if leftNum < rightNum.
  • The few tests impacted can be found in those commits: 04132ee, 252873c.
    • Only some spacing errors reported were removed, outputs are unchanged.

What is the purpose of this pull request?

• New Feature

[hugop95]

@OlivierZal 👋 Feel free to review this if you want 🙂

[azat-io]

Can you move this file to test/utils/?

[hugop95]

@azat-io Oops, rebase from #425 didn't move it 😅. Moved in f4b4ad5.

[OlivierZal]

Looks good to me!

[azat-io]

Can you tell me why you removed these tests?

[hugop95]

@azat-io

• The edited code responsible for those lines changes can be found here (see each commit's description)
  • 04132ee
  • 252873c
• Those changes are not absolutely required:
  • (1) Some spacing errors were reported after checking if leftNum < rightNum.
  • (2) Some other errors were not checking if leftNum < rightNum, leading to spacing errors being reported even when the nodes were not sorted.
  • I added the leftNum < rightNum for all cases => Spacing errors from (2) are now not reported.
• If needed, I can revert these commits. 🙂