As a note, if you modify or replace the sublime-package
file that ships with sublime, it will get reverted back to the default file again the next time that Sublime updates itself or if you re-install sublime.
To get around that, you can override only that specific file. The easiest way to do that would be to use PackageResourceViewer. You can select Package Resource Viewer: Open Resource
from the command palette, select HTML
and then Miscellaneous.tmPreferences
to open the file, and then make your changes and hit save.
That will create an override for only that particular file, where the changes will remain in effect even if/when Sublime updates or gets reinstalled.
Note that this also means that your override remains in effect even if the base version of the package modifies it.