This is a feature request to add a per-certificate Le_RenewHook field on the Advanced Settings tab. This would then get stored in the per certficate .conf file as
Le_RenewHook='/etc/init.d/uhttpd restart' (for example).
I have tried this manually to force a restart of uhttpd after a successful renewal and it works. Optionally, this particular renew hook could be generated by a checkbox on the General Settings tab next to or under the Use for uhttpd checkbox, such as:
Restart uhttpd upon renewal
Thanks for your consideration.