Using $this when not in object context

[ScullWM]

Hi thanks for this nice ServiceProvider!

Seem that the last update generate a Fatal error:
"Fatal error: Using $this when not in object context in" on Line 60.

Seems that the boot method can't access the jsContent method, probably bescause it's call in a lamba function.

Personnaly I've use a big content var to set the javascript content and replace elements.

Finaly (if i can help you) I won't use this ServiceProvider on my actual project because of all admin's url are available in a simple javascript file (I don't like this):
admin/user-{id}.html, admin/edit-user-{id}.html, admin/spy-user-{id}.html, admin/report-to-nsa-user-{id}.html, admin/engage-kill-for-user-{id}.html