ANSI coloring is broken when querying with field and no value

[Nagasaki45]

For example:

$ bibo list readdate:
[32mhuang2019nonverbal[0m 📁
Sandy H Huang, Isabella Huang, Ravi Pandya, and Anca D Dragan. Nonverbal robot feedback for human teachers. arXiv preprint arXiv:1911.02320, 2019.
[32mzhang2019coordination[0m [36mmimicry,VR[0m 📁 🔗
Leshao Zhang and Patrick G.T. Healey. Co-ordination of head nods: Asymmetries between speakers and listeners. In Proceedings of the 23rd Workshop on the Semantics and Pragmatics of Dialogue - Full Papers, London, United Kingdom, sep 2019. SEMDIAL.
[32mkousidis2013exploring[0m 📁
Spyridon Kousidis, Zofia Malisz, Petra Wagner, and David Schlangen. Exploring annotation of head gesture forms in spontaneous human interaction. In Proceedings of the Tilburg Gesture Meeting (TiGeR 2013), 2013.
[32mallwood2003study[0m 📁
Jens Allwood and Loredana Cerrato. A study of gestural feedback expressions. In First nordic symposium on multimodal communication, pages 7--22. Copenhagen, 2003.
...

The issue is definitely related to #58.