Repeated is_string_like function

[pelson]

matplotlib.is_string_like and matplotlib.cbook.is_string_like both exist, one is documented and handles some more corner cases. Do they both need to exist?

[jdh2358]

IIRC, we needed on in init.py so we copied the one out of cbook because matplotlib can't import from matplotlib.cbook. Probably the best thing to do is copy the one from cbook into init.py and then in cbook, import the one from matplotlib

[mdboom]

Agreed.

[NelleV]

I can work on this issue.

[dmcdougall]

Thanks, @NelleV.