Fix all non-CSS coding standards messages

Problem/Motivation

Currently the 8x-1.x branch has 11 Coding Standard messages. 4 Of them are CSS related.

11 coding standards messages
	
css/select2boxes.theme.css
line 2	Use of !important
3	Use of !important
4	Use of !important
11	Use of !important
modules/select2_bef/select2_bef.install
22	There should be no white space before a closing ")"
48	Expected 1 newline at end of file; 2 found
src/Plugin/Field/FieldWidget/MultiSelect2BoxesAutocompleteWidget.php
13	Unused use statement
src/PreloadBuildTrait.php
44	No space found before comment text; expected "// Sort all bundles, then convert back to numeric based index for javascript" but found "//Sort all bundles, then convert back to numeric based index for javascript"
44	Inline comments must end in full-stops, exclamation marks, question marks, colons, or closing parentheses
tests/modules/select2boxes_test_form/src/Form/Select2BoxesTestForm.php
19	Expected 1 blank line before function; 2 found
tests/src/FunctionalJavascript/Select2BoxesTestsBase.php
30	If the line declaring an array spans longer than 80 characters, each element should be broken into its own line

Steps to reproduce

Visit the Select2 Boxes Automated Testing page

Proposed resolution

The intention of this issue is the resolve all the other (non-CSS related) Coding Standard messages

So the end result would be:

4 coding standards messages
	
css/select2boxes.theme.css
line 2	Use of !important
3	Use of !important
4	Use of !important
11	Use of !important

Remaining tasks

Create patch/MR
Review
Commit
Rejoice

User interface changes

API changes

Data model changes