Bump nikic/php-parser to 5.4.0

[IanDelMar]

This PR updates nikic/php-parser from ^4.13 to ^5.4.

I reviewed the diff and found no unwanted changes resulting from the upgrade. The changes introduced by this PR result from changes in pretty-printing behavior in php-parser v5:

• Return types are now printed without a space before the colon (:).
• The abstract and final modifiers are now printed before visibility modifiers. Example: public final → final public.
• Backslashes in single-quoted strings are now escaped only when necessary. Examples: [\\d] → [\d], \\. → \., 'SimplePie\\Cache\\MySQL' → 'SimplePie\Cache\MySQL'.

In fact, php-parser v5 reverts changes introduced in version 4. For example:

// WP core:
final public function set_header_image( $choice ) {
    // ...
}

// Stub with nikic/php-parser v4:
public final function set_header_image($choice)
{
}

// Stub with nikic/php-parser v5:
final public function set_header_image($choice)
{
}

Related: php-stubs/generator#33

[szepeviktor]

So much change!
Who will fix it? 🙃

[IanDelMar]

Fix what?

[szepeviktor]

There was hundreds of changes.
I cannot tell whether they are okay.

[IanDelMar]

Sorry for the initially sparse — or missing, respectively — PR description. I’ve added it now. I’ll try to provide better context upfront in future PRs!

[szepeviktor]

I reviewed the diff and found no unwanted changes resulting from the upgrade. The changes introduced by this PR result from changes in pretty-printing behavior in php-parser v5:

Thank you!