allow face selectors to be relative to workplane ?

```
# testcase
wp = cq.Workplane("XY")

degree = 89

x = wp.transformed(rotate=(degree,0,0)) \
.circle(3, forConstruction = True).toPending() \
.workplane(offset=10) \
.circle(3, forConstruction = True).toPending() \
.loft() \
.faces(">Z") \
.workplane() \
.circle(2, forConstruction = True).toPending() \
.workplane(offset=10) \
.circle(2, forConstruction = True).toPending() \
.loft() \

from typing import Callable, Tuple
def waterfall(wp: cq.Workplane, fs: list[Callable[[cq.Workplane], Tuple[cq.Workplane, cq.Workplane]]]) -> cq.Workplane:
w1, w2 = wp, wp;
for f in fs:
w1, w2 = f(w2)
return w1

def trapez_cone(height, d1, d2 = None):
""" nur nach oben in Z Richtung wegen > Z"""
if d2 == None:
d2 = d1
def f(wp: cq.Workplane):
wp = wp.circle(d1, forConstruction = True).toPending() \
.workplane(offset=height) \
.circle(d2, forConstruction = True).toPending() \
.loft()
return (wp, wp.faces(">Z").workplane())

return f

b = waterfall(cq.Workplane("XY").transformed(rotate=(0,degree,0)),[
trapez_cone(10, 2, 2),
trapez_cone(10, 4, 4),
])
```

If you change degree to > 90 the hole in the middle is closed. So it would be nice if >Z would be relative to workplane Z direction not global Z direction or if z (lower case or such) would have this different behavior to not break code. or >wz (w meaning workplane) or whatever. The waterfall implementation basically is the same but allowing pyright to type the abstraction which it can't if you extend workplane