After upgrading git from 2.35.x to 2.36.0, highlighting commits that match a
path in gitk no longer works. Instead of only highlighting commits that touch a
certain path, all commits are highlighted.

To reproduce:

 * Use gitk to view a repository

 * Select a commit that modifies a file

 * In the right hand side pane, right click on a file and choose the "Highlight
this only" option

In git versions prior to 2.36.0, only commits that touched a file that matches
the path would have been highlighted.

In git 2.36.0 all commits are highlighted.