src/sage/rings/abc.pyx: Restore lost RealField

Author: Matthias Koeppe

src/sage/rings/abc.pyx

@@ -35,6 +35,14 @@ class AlgebraicField(AlgebraicField_common):
 
 
 class AlgebraicRealField(AlgebraicField_common):
+    r"""
+    Abstract base class for :class:`~sage.rings.qqbar.AlgebraicRealField`.
+    """
+
+    pass
+
+
+cdef class RealField(Field):
     r"""
     Abstract base class for :class:`~sage.rings.real_mpfr.RealField_class`.
     """