[prettierx] include Prettier 2.3.2 & PostCSS 8 updates

[brodycj]

updated:

• Include update to use PostCSS v8:
  • prettier/prettier@8616182
• Reapply prettierX language-js features based on Prettier 2.3.2, based on updates proposed by @adalinesimonian in PR Merge additional changes from adalinesimonian/merge-prettier-2.3.1 #603
• Use multiple merge commits with intermediate "version branches" to include the updates from Prettier 2.3.2 (in a similar manner to now abandoned PR [WIP] prettierx-update-branch-001-x - rebase some features with updates from Prettier 2.3.1 - UPDATE TEST WIP - NOW ABANDONED #616)
• Update many tests & test snapshots

The intermediate "version branches" with the multiple merge commits were made to help keep the changes in not-too-large commits as much as I think was reasonably practical. I think the major crux of the challenge was the amount of refactoring that has occurred between Prettier 2.0.5 and 2.3.x.

/cc @adalinesimonian

[brodycj]

The changes below to src/language-html/printer-html.js do not seem to trigger any test failures.

• TODO item is to improve testing of prettierX updates to src/language-html

--- a/src/language-html/printer-html.js
+++ b/src/language-html/printer-html.js
@@ -647,5 +647,5 @@ function printAttributes(path, options, print) {
   if (!isNonEmptyArray(node.attrs)) {
     // [prettierx merge update from [email protected]] --html-void-tags option:
-    return node.isSelfClosing && !isHtmlVoidTagNeeded(node, options)
+    return node.isSelfClosing
       ? /**
          *     <br />

---

--- a/src/language-html/printer-html.js
+++ b/src/language-html/printer-html.js
@@ -714,5 +714,5 @@ function printAttributes(path, options, print) {
     // [prettierx merge update from [email protected]] --html-void-tags option:
     parts.push(
-      node.isSelfClosing && !isHtmlVoidTagNeeded(node, options) ? " " : ""
+      node.isSelfClosing ? " " : ""
     );
   } else {

---

P.S. I discovered this through manual testing of changes after using git diff to check the differences with Prettier release 2.3.2. I think it would be ideal to start using a tool such as Stryker Mutator for mutation testing.

[brodycj]

• I would also like to find a way to resolve this warning message:

warning " > [email protected]" has unmet peer dependency "remark-parse@^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0".

---

My apologies, this was coming from 0.18.x branch.

[brodycj]

I am now thinking that the --html-void-tags option should be renamed to something like --html-void-elements, which should be a little more consistent with common nomenclature ref:

• https://www.456bereastreet.com/archive/201005/void_empty_elements_and_self-closing_start_tags_in_html/
• https://riptutorial.com/html/topic/1449/void-elements
• https://riptutorial.com/html/example/4736/void-elements
• https://stackoverflow.com/questions/4693939/self-closing-tags-void-elements-in-html5
• maybe some other results of: https://duckduckgo.com/?q=html+void+tags&ia=web

[brodycj]

I would also like to improve testing with mote tags, and across more parsers such as Glimmer & LWC. I just raised a couple of issues on Prettier which may be of interest:

• Fix unclosed tags with Vue prettier/prettier#11169
• Handling of missing close tags in Glimmer vs Angular, etc.? prettier/prettier#11170