[editorconfig] Turn off trim_trailing_whitespace in Markdown in root or changelog_unreleased

[tats-u]

Description

When EditorConfig is enabled in your text editor, you cannot use line breaking by adding two whitespaces at the end of lines in Markdown files in the project root or changelog_unreleased.

Checklist

• I’ve added tests to confirm my change works.
• (If changing the API or CLI) I’ve documented the changes I’ve made (in the docs/ directory).
• (If the change is user-facing) I’ve added my changes to changelog_unreleased/*/XXXX.md file following changelog_unreleased/TEMPLATE.md.
• I’ve read the contributing guidelines.

✨Try the playground for this PR✨

[sosukesuzuki]

Can you concat with the config for [website/blog/*.md]?

[tats-u]

@sosukesuzuki I have done. It seems to still work well.

PS> yarn editorconfig .\changelog_unreleased\markdown\.gitkeep
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\changelog_unreleased\markdown\.gitkeep
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=true
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.15s.

PS> yarn editorconfig .\changelog_unreleased\markdown\.gitkeep.md
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\changelog_unreleased\markdown\.gitkeep.md
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=false
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.14s.

PS> yarn editorconfig .\changelog_unreleased\BLOG_POST_INTRO_TEMPLATE.md
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\changelog_unreleased\BLOG_POST_INTRO_TEMPLATE.md
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=false
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.15s.

PS> yarn editorconfig .\changelog_unreleased\BL
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\changelog_unreleased\BL
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=true
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.15s.

PS> yarn editorconfig .\README.md
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\README.md
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=false
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.18s.

PS> yarn editorconfig .\src\foobarbaz.md
yarn run v1.22.4
$ I:\prettier\node_modules\.bin\editorconfig .\src\foobarbaz.md
charset=utf-8
indent_style=space
indent_size=2
trim_trailing_whitespace=true
end_of_line=lf
insert_final_newline=true
tab_width=2
Done in 0.15s.

[fisker]

I don't understand why we need this change.

[tats-u]

@fisker
I would like to add paragraphs like the following to a changelog for #11597. As you know, Markdown allows trailing 2 spaces and convert them to single <br />. I do not understand why we ban a specific specification in Markdown.

In Foo, Bar should not be Baz.

> Quotation. Quotation. Quotation.
>
> Quotation. Quotation. Quotation.

<https://a.source.example.com/>  
<https://b.source.example.com/>  
<https://c.source.example.com/>

Without this, I have to insert empty lines between URLs or use a list.

[tats-u]

I would like to cherry-pick this commit into#11597. Is this allowed?

[sosukesuzuki]

@tats-u I've merged main into next. Can you rebase latest next into #11597 ?

[sosukesuzuki]

I mistook something, Actions for next failed... I'll fix.

[tats-u]

@sosukesuzuki I will wait until Actions succeeds.

[fisker]

Markdown allows trailing 2 spaces and convert them to single
. I do not understand why we ban a specific specification in Markdown.

You may consider it's bug in Prettier, but this PR doesn't make sense, we keep trim_trailing_whitespace in editorconfig, but we still format these files by Prettier, the space will be moved again.

[fisker]

The only need in changelog_unreleased files is wrote some example code, but we can do something like

```markdown
foo<SPACE><SPACE>
```

Other cases we can use <br> or \

[fisker]

@sosukesuzuki ^

[tats-u]

@fisker

You may consider it's bug in Prettier, but this PR doesn't make sense, we keep trim_trailing_whitespace in editorconfig, but we still format these files by Prettier, the space will be moved again.

I am afraid that this is new to me. I would like you to check out the following sandbox showing that trailing 2 spaces are not deformed in the latest stable version of Prettier even when --prose-wrap is always.

https://prettier.io/playground/#N4Igxg9gdgLgprEAuEBiABAFTgZxgHSkIBkIAnOAW3QEsAHHAV2oBMIAbc9HGmdAQ0pwYAGnSQoOOGHgxGZAS3o0cYGlADm6OO15ipLdG201GOShEPxKdLurVKWjWOkZ92-AEbk42vm04KdEp+DSh+AV0AR0Z+ADp0AFU+BBpqfkNKdTT0ADdUwTEYlXQoCDwyRkM4AA84MjUYfhgaaFd2D0pIdA9vMhKoFRpXPn5oxnptGu0IyEoLYwkpGOaEgBEJnAE3XxpKoIC7KHQKOgoACwQWet5aY9yORjom+DydW9wpcRoO5iMOHzaRjoABmjA0NGapUYHQidH4-Wa8gSAFEamA4M84PJuOo+BAwGB+NIoWAnjQWM0oWVjmcIBSEKJuM4+OpxDD4ehiugICCQTQ1BFrlJKi4LB1bvxBtQKdo8D0vORmHFCIQADznGAwBhIAD0uo0EAgcQ07AAfOh0OrNdqcHqDUaTebLdatTr9YbjaazaqoIBEwnQMDI-B+6i0ACZuPCMVtahjnoHLgr5YkAErEX0at12j2O72u232z1On1QLOF3Ne82+gNlQPB0OaKP8GMgEQgCDPVqSZCgBFkCAAdwACgiEDhkCAxoP+ABPCftzzBsAAa2EAGVBHBiOo4MgQWMpIvl2uYOvo2HkEHGHB21RPHAWNcWMQpRpYho4AAxcghLWXlB+DcCA2xATVKHYAB1c5eFwaM4HXcdeBoXJeFnScwBwBcQHUEUYGHYMNBCfdD1vEAACscBqdcw3YOAAEVGAgeASPYI8QHhMgRUnEIyBXNhBygUCzjxSCKRgc5kAADgABnbOkpEg4M6Enac52wmJmLgAjOwnQCcAAWigOBH0fUCKGKCgCNCYikAPNiyKkLIr0qRzaIYpiWLs0j2yaTwxJYCTkHDXyG10TQAGEIHmfhJ1wABWUCzDgTAvD0+z2NyG8AEkoGuWB1zAfpngAQTy9cYFnOjWKkABfWqgA

Also, there seem to be no .prettierrc mentioning the configuration for Markdown or --prose-wrap.

[fisker]

@tats-u turns out I got confused by #6793, I thought markdown remove that too.... I'm sorry.

[tats-u]

@fisker You had me worried. I am relieved that it turned out to be just your misunderstanding.

[tats-u]

@sosukesuzuki I did it because I confirmed that the CI of fa59637 passed.

[sosukesuzuki]

@tats-u Ah sorry, I forgot to say you that.