Add post_title_child_separator filter

[vijendrajat]

Introduces the post_title_child_separator filter in WP_Posts_List_Table::column_title(), allowing the hardcoded em-dash hierarchy indicator to be replaced with a custom string. The separator string is passed through the filter once and then repeated per hierarchy level.

Renames the internal $pad variable to $separator for clarity.

Trac ticket: https://core.trac.wordpress.org/ticket/39106

Use of AI Tools

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