Fix the issues reported by phpcs (selectively)

Problem/Motivation

FILE: /var/www/html/web/modules/custom/ief_complex_open/src/Plugin/Field/FieldWidget/InlineEntityFormComplexOpen.php
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FOUND 16 ERRORS AND 5 WARNINGS AFFECTING 21 LINES
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  27 | ERROR   | [ ] Doc comment short description must be on a single line, further text should be a separate paragraph
  74 | ERROR   | [ ] The array declaration extends to column 86 (the limit is 80). The array content should be split up over multiple lines
  82 | WARNING | [x] 'TODO - does this belong in #element_validate?' should match the format '@todo Fix problem X here.'
 139 | ERROR   | [ ] The array declaration extends to column 84 (the limit is 80). The array content should be split up over multiple lines
 145 | ERROR   | [ ] The array declaration extends to column 88 (the limit is 80). The array content should be split up over multiple lines
 268 | WARNING | [ ] Unused variable $hide_cancel.
 273 | WARNING | [ ] Unused variable $hide_cancel.
 284 | ERROR   | [ ] The array declaration extends to column 85 (the limit is 80). The array content should be split up over multiple lines
 287 | WARNING | [ ] Unused variable $hide_cancel.
 293 | ERROR   | [ ] The array declaration extends to column 83 (the limit is 80). The array content should be split up over multiple lines
 295 | ERROR   | [ ] Inline doc block comments are not allowed; use "/* Comment */" or "// Comment" instead
 322 | ERROR   | [ ] Inline doc block comments are not allowed; use "/* Comment */" or "// Comment" instead
 327 | WARNING | [ ] Line exceeds 80 characters; contains 91 characters
 334 | ERROR   | [ ] The array declaration extends to column 101 (the limit is 80). The array content should be split up over multiple lines
 381 | ERROR   | [ ] Inline doc block comments are not allowed; use "/* Comment */" or "// Comment" instead
 406 | ERROR   | [ ] The array declaration extends to column 86 (the limit is 80). The array content should be split up over multiple lines
 416 | ERROR   | [ ] Parameter $reference_form is not described in comment
 418 | ERROR   | [ ] Doc comment short description must be on a single line, further text should be a separate paragraph
 424 | ERROR   | [ ] Missing parameter type
 426 | ERROR   | [ ] Missing parameter type
 431 | ERROR   | [ ] Public method name "InlineEntityFormComplexOpen::reference_form_submit" is not in lowerCamel format
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PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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Steps to reproduce

Run the command phpcs --standard="DrupalPractice,Drupal" ief_complex_open

Proposed resolution

Resolve coding standard issue and create the patch.

Remaining tasks

User interface changes

API changes

Data model changes