threadid() and nthreads() usage

[cormullion]

From this blog post we read that:

Any usage of threadid() in package or user code should be seen as a warning sign that the code is relying on implementation details, and is open to concurrency bugs.

In Luxor threadid() does appear a few times:

• Luxor.jl/src/drawings.jl

  Line 90 in 18d96c8

   id = Threads.threadid() 

• Luxor.jl/src/basics.jl

  Line 553 in 18d96c8

   id = Threads.threadid() 

so there might be the possibility of issues and/or bugs.

[hustf]

Oops, we ought to think this through. I have used the thread features some on Julia 1.9 and did not notice any issues.