[Block] Display paragraph breaks in comment contents block.

[peterwilsoncc]

What?

Fixes #40248.

Apply comment_text filter in comment template to ensure paragraph breaks, smilies, links, etc are displayed.

Why?

Ensure comments in a block theme are displayed with the original paragraph breaks included during authoring. Presently the content is shown as one blob which can become difficult to read.

How?

Traditional WP themes use comment_template() to echo the comment content.

function comment_text( $comment_ID = 0, $args = array() ) {
	$comment = get_comment( $comment_ID );

	$comment_text = get_comment_text( $comment, $args );
	/**
	 * Filters the text of a comment to be displayed.
	 *
	 * @since 1.2.0
	 *
	 * @see Walker_Comment::comment()
	 *
	 * @param string          $comment_text Text of the current comment.
	 * @param WP_Comment|null $comment      The comment object. Null if not found.
	 * @param array           $args         An array of arguments.
	 */
	echo apply_filters( 'comment_text', $comment_text, $comment, $args );
}

The final echo statement rules out it's use for rendering the template block but applying the same filter ensures parity in display between the comment loop and comment template.

Testing Instructions

1. Test using WP 5.9 (trunk will use the previously merged functions)
2. Enable 2022 with a block theme using the comment query loop
3. Checkout gutenberg trunk
4. Leave a comment with two or more paragraphs
5. View the comment on the front end, observe it's one blob of text.
6. Switch to this branch
7. Reload the front end and your paragraphs will be visible once again.

Screenshots or screencast

Before

After

[peterwilsoncc]

Real talk: Even though I wrote it, I don't know how I feel about this. autop puts in some weird line breaks that I want to ignore but a line break is white space rather than an empty string.

[paaljoachim]

I assume we should backport the fix to WP 6.0 beta.

[cbravobernal]

Worked like a charm!

[adamziel]

@c4rl0sbr4v0 @peterwilsoncc @ockham @paaljoachim a corresponding PR against wordpress-develop will be needed to include these unit tests in WordPress 6.0. Is it something you want? If so, would you please create one?

[adamziel]

I cherry picked this change into wp/6.0 branch to be included in WordPress 6.0 Beta 4 on Monday: 379461d

[ockham]

@c4rl0sbr4v0 @peterwilsoncc @ockham @paaljoachim a corresponding PR against wordpress-develop will be needed to include these unit tests in WordPress 6.0. Is it something you want? If so, would you please create one?

@DAreRodz kindly took care of this: WordPress/wordpress-develop#2649

[gziolo]

Awesome, I guess we will have merge those changes into WordPress/wordpress-develop#2651 to get green checks on CI 👍🏻