Doc - Unified index

[Bertalan Fodor]

When installing Documentation on Windows, which doesn't distinguish between
uppercase and lowercase letters in file names, unified Index is not
installed, because it is called 'Index.html', and there is another file
called 'index.html'. So Index.html gets overwritten.

Could the filename of Index.html be changed? (Perhaps that would mean that
the Texinfo Index node should be changed, which is generated by
@printindex.)

Greetings,
Bert