Modernize: use explicit visibility for property declarations

[jrf]

Using var or just and only static to declare a class property is PHP 4 code. PHP 5 introduced visibility modifiers.

This updates the code base to use explicit visibility modifier for properties.

No review has been done on what the visibility of the properties should be as a property without visibility defaults to public and changing that to a more closed visibility would be a BC-break.

Note: the same should be done for class methods at some point, but I wouldn't want the fixes for that to interfere with patches for ticket #51533, so I'm leaving that till later.

Related to #50767

Using var or just and only static to declare a class property is PHP 4 code. PHP 5 introduced visibility modifiers.

This updates the code base to use explicit visibility modifier for properties.

No review has been done on what the visibility of the properties _should_ be as a property without visibility defaults to public and changing that to a more closed visibility would be a BC-break.

Trac ticket: https://core.trac.wordpress.org/ticket/51557

[jrf]

Fixes all known instances of this issue

[SergeyBiryukov]

Previously: #22234

[SergeyBiryukov]

In 49184:

Code Modernization: Use explicit visibility for class property declarations.

Using var or only static to declare a class property is PHP 4 code.

This updates the codebase to use explicit visibility modifiers introduced in PHP 5.

Props jrf.
Fixes #51557. See #22234.

[jrf]

Thanks @SergeyBiryukov for committing and finding the previous ticket, I did search, but my trac search-fu is nowhere near as good as yours ;-)

Closing as committed.