The file was originally named `higan-config.md` because the dialog box
it described was called "higan Configuration", which was because the
menu-item to open it was in a menu called "Settings" and it would have
been weird to have a "Settings" item in a "Settings" menu.
Now there are individual menu-items for each tab in the Settings dialog,
none of which are named Settings, so the dialog has been renamed back to
"Settings", and the filename should match.
Also, some of the text in the higan and icarus settings docs wanted to
link to a discussion of why we ignore manifests by default; now we have
such a thing.
The existing documentation was getting *way* too long to be a single
document.
I've just bulk moved the existing content into the new structure, but it
definitely needs another pass to make the prose match, fix hyperlinks,
etc. etc.
Tim Allen