The goal is to allow passing template parameters in the string that is passed
to `RNA_def_function` in rna code. This can reduce redundancy (e.g. when used
together with #113114). Only "simple" template parameters are supported,
i.e. only ones that do not contain a nested `,`.
Function names passed to e.g. `RNA_def_property_pointer_funcs` and
`RNA_def_property_update` happen to support this already without further changes.
Pull Request: https://projects.blender.org/blender/blender/pulls/113121
690a3ddf7e