The comment_edit_pre filter allows you to do X.
It is evaluated in WP_Comments_List_Table::column_comment() in the wp-admin/includes/class-wp-comments-list-table.php file.
comment_edit_pre accepts a single argument:
Example:
View the code example on Gist.
Have a suggested improvement? You can fork the Gist and comment back with the link. If all is agreeable, I’ll merge in your changes. Crowd-sourced documentation FTW!