Add expit alias to xtensor math

Author: ricardoV94

pytensor/xtensor/math.py

@@ -101,7 +101,7 @@ def _as_xelemwise(core_op: ScalarOp) -> XElemwise:
 maximum = _as_xelemwise(ps.scalar_maximum)
 minimum = _as_xelemwise(ps.scalar_minimum)
 second = _as_xelemwise(ps.second)
-sigmoid = _as_xelemwise(ps.sigmoid)
+sigmoid = expit = _as_xelemwise(ps.sigmoid)
 sign = _as_xelemwise(ps.sign)
 sin = _as_xelemwise(ps.sin)
 sinh = _as_xelemwise(ps.sinh)