[Rector] Remove @var from class constant

[samsonasik]

I created new custom rector rule RemoveVarTagFromClassConstantRector to remove @var from class const per this discussion #4759 (comment)

Checklist:

• Securely signed commits

[kenjis]

Why don't we remove this Rector?
I don't see the need to delete @var that someone wrote.

The @var tag defines which type of data is represented by a value of a Constant, Property or Variable.
https://github.com/php-fig/fig-standards/blob/master/proposed/phpdoc-tags.md#518-var

[MGatner]

I don't have a strong opinion. My original point was that the @var tag is unnecessary on constants because their type is apparent at runtime. If it's helpful for devs to indicate that explicitly on the code then a comment could always be used without the tag.

I suppose an argument could be made for non-native types, like:

/**
 * @var class-string<Model>
 */
public const $model = Widget::class;