Module packages using different letter-casing appear multiple times

Tested patch #77 by using Action and Automated Cron.
Changed Action to User interface
Changed Automated Cron to User Interface

Verified they appear as separate "packages" on the modules patch
Applied the patch and they are grouped together.

Seems like something a simple test could be added for but this is a minor issue so maybe it is overkill.

Checking RTBC issues. There are no unanswered questions here. I see that there are no tests but that is explained in #73. This is making a change for the UI but there are no before and after screenshots to demonstrate that this is working as intended. This is needed in all cases where the UI is change, even more so here when there are no tests.

Tagging for screenshots which should be in or linked to from the Issue Summary so they are easy to find. I went to add this to the remaining tasks but it is already listed.

Holy moly, it has a D8 beta evaluation. Old issue alert.

1. This should have a change record and a release note snippet, since it's both changing the behavior for these keys and also altering how core (and potentially Project Browser in a followup?) sort and list data from Drupal.org's project info.

   We might also want to check with the infra team about this -- I don't know if d.o currently does anything with this data or not, but if we're changing the way core lists modules and d.o is able to extract the package and use it somehow, d.o would probably also need a parallel change.

2. +++ b/core/modules/system/src/Form/ModulesListForm.php
   @@ -190,9 +190,11 @@ public function buildForm(array $form, FormStateInterface $form_state) {
   +        // capitalization are grouped.
   

   Nit: Capitalizations.

3. +++ b/core/modules/system/src/Form/ModulesListForm.php
   @@ -204,15 +206,17 @@ public function buildForm(array $form, FormStateInterface $form_state) {
   +      // Use the first module's package label as $package_key is normalized.
   

   This is a little confusing. I think it is trying to say:

   Use the first module's package label, because the $package_key value has already been normalized.

4. +++ b/core/modules/system/src/Form/ModulesListForm.php
   @@ -204,15 +206,17 @@ public function buildForm(array $form, FormStateInterface $form_state) {
   +      $package = $modules[key($form['modules'][$package_key])]->info['package'];
   

   A question about the actual functionality here. If there are multiple labels for the same package name, especially due to casing issues, presumably some are canonical (Sentence case labels) whereas some might be malformatted (Title Case Labels or lowercase labels). So, by defaulting to whatever is first in the array, are we perhaps overwriting a good label format with a bad one?

   Should we have additional functionality to Title case the label if there are multiple versions that differ only by casing?

   And what if the labels differ by more than their casing? What if they legitimately belong in different groups and it's the package key that's completely wrong?