The renaming without file extension was in 0.5.0 as well - a requested feature.
Someone else could comment if it really matters - since xhtml is certainly valid.
Whether the feature needs to be modified to allow you to overrule the selection to change the file type is another question. Right now if you modify xhtml to html you get .html.xhtml
If its really needed, you could submit an issue about it, but it probably isn't a real issue.