Mark Niebergall

Add short array syntax

1

Added declaring arrays with short array syntax in Keywords and Types section with the "Short form of type keywords MUST ...".

Added section 12 specifying array use. Section 11 is used by https://github.com/php-fig/per-coding-style/pull/26. Applies guidelines like 2.6 Trailing Commas and 4.7 Method and Function Calls to array. If this PR is...

Array Declaration must be short array syntax

4

Currently all of the PSR/PER code examples show using PHP short array syntax `$thing = [];`. PRs (ex: https://github.com/php-fig/per-coding-style/pull/18) also use short array syntax `$arr = ['a' => 'A', 'b'...