Code Modernization: Declare dynamic properties on WP_Text_Diff_Renderer_Table.
Core uses 3 known, named, dynamic properties on the WP_Text_Diff_Renderer_Table class:
_title
_title_left
_title_right
When reviewing revisions (within the admin UI), wp_text_diff() passes the arguments (without the leading _) to a new instance, which raised deprecation notices (see [56354]).
Note: the parent class adds the leading _ to each of these properties (see [7747]).
The deprecation notices are resolved by declaring each of these known, named, dynamic properties on the class, per the #56034 mitigation strategy. These new properties are not initialized to retain their previous null behavior.
Follow-up to [56354], [23506], [7747].
Props wildworks, antonvlasenko, hellofromTonya, ironprogrammer, kafleg, mukesh27, nicolefurlan, presskopp, sabernhardt.
Fixes #59431.
See #58898, #56034.