* Better argument handling of front-end-root
Improves handling of front-end-root launch argument. Several instances where users have set it and ComfyUI launches as normal and completely disregards the launch arg which doesn't make sense. Better to indicate to user that something is incorrect.
* Removed unused import
There was no real reason to use "Optional" typing in ther front-end-root argument.
* Fix link pointing to non-exisiting docs
The current link is pointing to a path that does not exist any longer.
I changed it to point to the currect correct path for custom nodes datatypes.
* Update node_typing.py