Feature summary (what you would like to be able to do and where):
Renaming should NOT treat file extensions as equal to each other. As in, when trying to rename, you can rename an .oga file to an .ogg file, and a .tif file to a .tiff file.
Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):
When trying to rename this file to Concert for you.ogg, the renamer accidentally renamed it to Concert for you.oga. The problem is, while renaming treats .oga as better than .ogg, meaning you can’t rerename it, the Mediawiki system doesn’t, meaning that they are treated as two separate files.
Benefits (why should this be implemented?):
This is useful when the file extension itself is important to maintain a set (EXAMPLE1.JPG, EXAMPLE2.JPG, EXAMPLE3.jpg), or when the file extension is important to the name itself (Plain.tiff vs Plain.tif).