Enable no_trailing_comma_in_singleline

[paulbalandan]

Description

$ vendor/bin/php-cs-fixer describe no_trailing_comma_in_singleline
Description of no_trailing_comma_in_singleline rule.
If a list of values separated by a comma is contained on a single line, then the last item MUST NOT have a trailing comma.

Fixer is configurable using following option:
* elements (a subset of ['arguments', 'array_destructuring', 'array', 'group_import']): which elements to fix; defaults to ['arguments', 'array_destructuring', 'array', 'group_import']

Fixing examples:
 * Example #1. Fixing with the default configuration.
   ---------- begin diff ----------
   --- Original
   +++ New
   @@ -1,5 +1,5 @@
    <?php
   -foo($a,);
   -$foo = array(1,);
   -[$foo, $bar,] = $array;
   -use a\{ClassA, ClassB,};
   +foo($a);
   +$foo = array(1);
   +[$foo, $bar] = $array;
   +use a\{ClassA, ClassB};

   ----------- end diff -----------

 * Example #2. Fixing with configuration: ['elements' => ['array_destructuring']].
   ---------- begin diff ----------
   --- Original
   +++ New
   @@ -1,3 +1,3 @@
    <?php
    foo($a,);
   -[$foo, $bar,] = $array;
   +[$foo, $bar] = $array;

   ----------- end diff -----------

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

I'm going to get some of these in so they can make it in the release.