[FR] Differentiate Subpatch objects graphically

[alcomposer]

Subpatch objects (starting with PD) enable a user to click on, and open up another patcher, that is nested in the parent patch.

However there is currently no visual way that we display these teleporting objects.

It helps to see visually at a glance when they are used, so that a user can see the layout and understand how the patch works.

Here is a suggestion, to use a triangle, with a chevron positioned to the right of the object to symbolise that these objects open an external patch. For objects that simply open a floating window, use only the triangle and omit the chevron: