Not all entries in the directory stack are Path objects

[illright]

Steps to reproduce

• Execute %cd /home
• Execute _dh

Expected result

A list of Path objects is printed: [PosixPath('/some/starting/path'), PosixPath('/home')]

Actual result

A mixed list of Path objects and strings is printed: [PosixPath('/some/starting/path'), '/home']

System info

Manjaro Linux, Python 3.9.4, IPython 7.22.0 (reproduces on IPython 8.0.0.dev)

[GalBr]

This issue should be fixed as part of the work in #12515. We append to dhist (_dh) in osm.py (specifically in the cd() function) and we use os.getcwd() right now, which should be changed to Path.cwd().