Sneathia vaginalis sp. nov. (Fusobacteriales, Leptotrichiaceae) as a replacement of the species 'Sneathia amnii' Harwich et al. 2012 and 'Leptotrichia amnionii' Shukla et al. 2002, and emended description of Sneathia Collins et al. 2001. Issue 3 (22nd March 2021)