Update drupal.org and kernel.org URLs in core modules (Follow-up to 2489912)

The patch looks good and applies cleanly.

The particular instance that I saw originally on the installer pages has been fixed, so I think that it's good to go.

I got 1 more file which was not included at the first patch: .gitattributes
I'm also adding kernel.org to the changes. It is just one line in this same file.

I also found one http://drupal.com/trademark at README.txt, but https do not work well there and there is no redirect if using www. or not. Then, I did not modify this one.

I just found more entries at test files.

Note that there are entries that shall not be modified, as they are used to create and test http/https links:
./core/modules/link/tests/src/Plugin/Validation/Constraint/LinkExternalProtocolsConstraintValidatorTest.php

  public function providerValidate() {
    $data = [];

    // Test allowed protocols.
    $data[] = ['http://www.drupal.org', TRUE];
    $data[] = ['https://www.drupal.org', TRUE];

And ./core/tests/Drupal/Tests/Core/Validation/Plugin/Validation/Constraint/PrimitiveTypeConstraintValidatorTest.php

    $data[] = [new Uri(DataDefinition::create('uri')), 'http://www.drupal.org', TRUE];
    $data[] = [new Uri(DataDefinition::create('uri')), 'https://www.drupal.org', TRUE];

test failed. Also this is not changing just documentation.

+++ b/sites/example.sites.php
@@ -21,18 +21,19 @@
+ * @link https://www.drupal.org/documentation/install online Drupal installation
+ * guide @endlink for more information on setting up domains, subdomains, and

See https://www.drupal.org/coding-standards/docs#link

The entire @link ... @endlink must be on the same line

There are more tags like this one that need to be fixed.

Thanks @opdavies et al. I reviewed this locally with:
git diff --staged --color-words=[,\.:]+|[^[:space:]]

Phew!

@jhodgdon is correct that, while this patch mostly changes only documentation, it also includes changes to links in user-facing strings as well as a couple tests. I looked over the test changes carefully to ensure the intent of the tests wasn't being changed (especially for the URL tests). Thanks for documenting the instances that should not be changed in the summary.

All of documentation, user facing strings, and tests are unfrozen, so this patch is okay to go in during the beta. It might require rerolls in a few other patches, but since it's mostly in @todo and such I think the disruption is limited enough to be acceptable, and better to get this disruption out of the way now so that other improvements to MAINTAINERS.txt and so on don't conflict with it. (Plus it's somewhat embarrassing to have non-canonical links to our own website.) ;) So, committed and pushed to 8.0.x.

This changes JS files, please tag it with "JavaScript".

It's hard to keep chasing head with #2182153: [Meta] Document Drupal JavaScript using JSDoc, I'd prefer to know about all JS issues to get ready to reroll when necessary.

All right @nod_. I will keep an eye on JS changes for the Link module.