Add BRep_Tool.CurveOnSurface_r returning (pcurve, first, last) (#167)

[GabrielJMS]

Summary

Fixes #167.

BRep_Tool::CurveOnSurface returns a non-void Handle(Geom2d_Curve) and reports the
edge's parameter range through reference arguments (Standard_Real& First, Standard_Real& Last).
Because Standard_Real maps to an immutable Python float, those outputs cannot be written
back to the caller, so the parameter range is unreachable from Python — which blocks the
parametric-space (UV) workflows described in the issue.

The existing call-by-reference → tuple mechanism (is_byref in pywrap) only triggers for
void-returning methods, so a non-void method like this one is missed.

Change

A targeted, non-breaking workaround via the rules mechanism (as suggested in the issue
thread — "add workaround method in the binding manually or via rules"). It adds a new static
method and leaves the original CurveOnSurface_s binding untouched:

[Modules.BRep.Classes.BRep_Tool.additional_static_methods.CurveOnSurface_r]
body = "[](const TopoDS_Edge& E, const TopoDS_Face& F){ Standard_Real first, last; auto curve = BRep_Tool::CurveOnSurface(E, F, first, last); return std::make_tuple(curve, first, last); }"

Usage:

from OCP.BRep import BRep_Tool
curve, first, last = BRep_Tool.CurveOnSurface_r(edge, face)

The _r suffix denotes "reference outputs returned as a tuple". Only the edge-on-face
overload is wrapped here.

Questions for the maintainers

@adam-urbanczyk

1. Does this targeted approach look acceptable? It mirrors the existing
   additional_static_methods precedents and changes no existing signatures.

2. Would you prefer a more general implementation instead? The void call-by-reference
   tuple handling could be generalized to also cover non-void methods whose outputs come
   back through immutable-type references (Standard_Real/Standard_Integer/Standard_Boolean),
   auto-generating these tuple variants — i.e. the same treatment void functions already get.
   That would be a change in pywrap (relaxing the void-only gate in is_byref and
   extending the byref lambda in template_sub.j2 to prepend the return value to the tuple),
   not in this repo. Happy to open that as a separate pywrap PR if you'd rather solve it
   generally.