Incorrect break (</br>) tag

Don't mind me. Im learning how to contribute (currently failing at it =P)

@Lms300: Don't panic, MRs are hard in the beginning.

As you might have found out by now, don't actually click the button "create a merge request" until there are code changes committed to it. Then the test result of TestBot will always be "Not currently mergeable."

Added patch for this.

Made changes as per comment #12.

Fixing the fail tests.

I have applied the patch #15 and reviewed the changed file in drupal 9.3.x-dev version.
This has fixed the tag <br/> to <br /> in mentioned files.
Adding screenshots for reference.

I'm pretty sure an issue can't be Reviewed & tested by the community when the latest patch doesn't apply and the previous patch has 1 error on Drupal CI, back to Needs Work so the latest patch can be re-rolled.

Also put the Version to 9.3.x-dev, since that's where new bugs should be fixed first. Then a Core Committer will backport it. I also added the Needs reroll tag.

Re-roll patch given for 9.3.x.

Thanks @vsujeetkumar. TestBot seems to have problems with diskspace at the moment, pinged "People With Knowledge" on Slack (https://drupal.slack.com/archives/C51GNJG91/p1621934020018300).

Until that is fixed (the actual people are in US-timezone) there's not I/we can do about it than wait I'm afraid.

Fixing CI error, Please have a look.

Patch updates tags correctly, just one question. Are the comments changes ok? Are they in scope or there no issue? In case they are okay I believe it is RTBC.

Re-uploaded patch removing changes in comments as they are out of scope, and one of them separates comment related to different things.

I think we need to change it in FinalExceptionSubscriberTest.php as well:
$this->stringStartsWith('The website encountered an unexpected error. Please try again later.</br></br><em class="placeholder">Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException</em>: test message in ', $response->getContent());

I applied the patch #23, which correctly updates the () tags. It's just missing the interdiff @guilhermevp.

Updated patch based on comment #25 and created a interdiff of 21-23 to make the code changes easier to follow as asked by comment #27, please review, and thanks for the feedbacks!

I found tow more places with the incorrect tag.
StandardTest.php

    $data[] = ['<STYLE>li {list-style-image: url("javascript:alert(\'XSS\')");}</STYLE><UL><LI>XSS</br>', 'li {list-style-image: url("javascript:alert(\'XSS\')");}<UL><LI>XSS</br>'];

    $data[] = ['<STYLE>li {list-style-image: url("javascript:alert(\'XSS\')");}</STYLE><UL><LI>XSS</br>', 'li {list-style-image: url("javascript:alert(\'XSS\')");}<UL><LI>XSS</br>'];

FilterKernelTest.php
$f = Html::normalize('<br></br>');

In HTML5 only <br> is needed as it is now a void element rather than self-closing, I think in the spirit of modernisation we should move to using HTML5 standards.

Re #31 those two tests should be left alone, the first is a very specialised test for cross site scripting and the second is checking that improperly formed HTML is normalised correctly.

New patch and interdiff.

Thanks, #34 looks good - to me this is RTBC assuming bot agrees.

Crediting @longwave for direction, @Spokje for mentoring

Given we normally avoid markup changes in minor versions, I'm going to leave this as 9.3.x only.

Thanks all

Committed 967e167 and pushed to 9.3.x. Thanks!