Documentation update - BTSubTree

[onze]

Added a note about updating subtree at runtime.

[limbonaut]

The content is good, but the files under doc/source/classes/ are auto-generated using godot's make-rst.py script. You need to change related XML-file in doc_classes/ instead.

[onze]

Right. So, it turns out that per the class xsd, links don't seem to be allowed, and I couldn't hardcode the rst in there either, so here it is plain 🤮
Feel free to suggest a better alternative.

[limbonaut]

This is how I generate the rst part:

#!/bin/sh
./doc/tools/make_rst.py --output /tmp/rst doc/tools doc/classes/@GlobalScope.xml modules/limboai/doc_classes
rsync /tmp/rst/class_* modules/limboai/doc/source/classes/ --exclude class_@globalscope.rst

You'd need godot sources (4.2 branch) with limboai sources deployed in modules/limboai.
But you don't need to bother with the rst part - I always update rst before release.

[limbonaut]

Thanks!