Make sure the code aligns with Drupal coding standards

To get this theme to full release we need to make sure our code is up to scratch according to the Drupal coding standards.

Using the PAReview tool we've managed to squish a lot of the issues and now it's down to just a few, with the last of the reviews here.

The funny thing with the css "errors" is that the errors it's pointing out don't exist in the file, so I think we can get away with leaving those for now.

What we're left with is a few things in the bones.theme file:

FILE: ...0000/site1101/web/vendor/drupal/pareviewsh/pareview_temp/bones.theme
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FOUND 3 ERRORS AFFECTING 3 LINES
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 17 | ERROR | [ ] Type hint "array" missing for $variables
 18 | ERROR | [x] Short array syntax must be used to define arrays
 22 | ERROR | [x] Short array syntax must be used to define arrays
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PHPCBF CAN FIX THE 2 MARKED SNIFF VIOLATIONS AUTOMATICALLY
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Looks like it would be easiest to use PHPCBF to fix them, like the suggestion says.