Text spacing rewrite

[Jym77]

With #1804, the text spacing rules becomes way too complex.
This simplifies them by looking at the text directly rather than at the style attribute. This automatically solves all the problems about inheritance, changed values, … by making sure that we only look at values that are actually used.

I feel this version is much simpler even than the current version.

• Failed testcases stay the exact same.
• Some Passed cases are now Inapplicable.
• Added 3 Passed/Inapplicable cases corresponding to the ones listed in Text spacing not !important rules should check text is actually affected [78fd32, 24afc2, 9e45ec] #1687 and Text spacing not !important does not account for actual font-size [78fd32, 24afc2, 9e45ec] #1688.
• Added an assumption about the text using the corresponding property. This matches an exception in WCAG.
• Copied the assumption from "line height" rule, that font-size isn't changed through ::first-line or other, to other rules.

Closes issue(s):

• closes Text spacing not !important rules should check text is actually affected [78fd32, 24afc2, 9e45ec] #1687
• closes Text spacing not !important does not account for actual font-size [78fd32, 24afc2, 9e45ec] #1688
• supersedes Text spacing not !important [78fd32, 24afc2, 9e45ec]: Consider actual font size and ignore empty text #1804

Need for Call for Review:
This will require a 2 weeks Call for Review (new versions of the rules, including heavy changes and simplification)

---

Pull Request Etiquette

When creating PR:

• Make sure you're requesting to pull a branch (right side) to the develop branch (left side).
• Make sure you do not remove the "How to Review and Approve" section in your pull request description

After creating PR:

• Add yourself (and co-authors) as "Assignees" for PR.
• Add label to indicate if it's a Rule, Definition or Chore.
• Link the PR to any issue it solves. This will be done automatically by referencing the issue at the top of this comment in the indicated place.
• Optionally request feedback from anyone in particular by assigning them as "Reviewers".

When merging a PR:

• Close any issue that the PR resolves. This will happen automatically upon merging if the PR was correctly linked to the issue, e.g. by referencing the issue at the top of this comment.

How to Review And Approve

• Go to the “Files changed” tab
• Here you will have the option to leave comments on different lines.
• Once the review is completed, find the “Review changes” button in the top right, select “Approve” (if you are really confident in the rule) or "Request changes" and click “Submit review”.
• Make sure to also review the proposed Call for Review period. In case of disagreement, the longer period wins.

[Jym77]

Target text nodes rather than elements (+ note that CSS property is actually on parent).
Replace old rules rather than create new ones.

letter spacing updated

[Jym77]

@WilcoFiers I've updated the letter-spacing rule. Can you look at it and see if it's OK? If so, I'll keep going with the other two.

[carlosapaduarte]

Is the computed value important?
Or is it the declaration of the letter-spacing property that is important?
The important declaration influences how the computed value is obtained, but I'm not sure we can say the computed value is important....

[Jym77]

Good point. We do need to somehow look at the computed value due to Inapplicable Example 8, where the inherit !important declaration is important but we don't care because the computed value is the inherited one, coming from a non-important declaration and thus can be overwritten.
I do agree that only declarations seems to be important 🙈

Given that this wording is already present in the current rule (first bullet in Expectation + Passed Example 7), I suggest we treat that in another Issue/PR: #2002

[dd8]

I've added a comment on #2002 on a way to deal with this

Concerns answered

[carlosapaduarte]

Still a spelling issue

Changes accepted

[tbostic32]

Little editorial to the applicabilities, but otherwise I think these look good.

[Jym77]

Call for reviews end on October 12.

[Jym77]

Call for review has ended, merging.