Fix codings standards issues

Review of the 8.x-1.2 branch (commit 201bf8a):
Your README.md does not follow best practices (headings need to be uppercase). See https://www.drupal.org/node/2181737 .
The INTRODUCTION section is missing.
The REQUIREMENTS section is missing.
The INSTALLATION section is missing.
The CONFIGURATION section is missing.
The contact_indexing.module does not implement hook_help(). See https://www.drupal.org/docs/develop/documenting-your-project/module-docu... .
Coder Sniffer has found some issues with your code (please check the Drupal coding standards). See attachment.
No automated test cases were found, did you consider writing PHPUnit tests? This is not a requirement but encouraged for professional software development.
This automated report was generated with PAReview.sh, your friendly project application review script.

FILE: ...000000/site1101/web/vendor/drupal/pareviewsh/pareview_temp/README.md
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FOUND 0 ERRORS AND 3 WARNINGS AFFECTING 3 LINES
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1 | WARNING | Line exceeds 80 characters; contains 153 characters
2 | WARNING | Line exceeds 80 characters; contains 112 characters
11 | WARNING | Line exceeds 80 characters; contains 91 characters
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FILE: ...1/web/vendor/drupal/pareviewsh/pareview_temp/contact_indexing.module
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FOUND 3 ERRORS AFFECTING 3 LINES
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42 | ERROR | [ ] Parameter tags must be grouped together in a doc
| | comment
45 | ERROR | [ ] Type hint "array" missing for $form
47 | ERROR | [x] Concat operator must be surrounded by a single space
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PHPCBF CAN FIX THE 1 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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Time: 415ms; Memory: 4Mb