index.d.ts: fixup types
index.d.ts: fixup types

These changes were made by hand, based on the documentation.

Perhaps in the future we can embed type info in the documentation in a way
that makes the generator able to pick them up, but right now this is easier
to do by hand.

fusetools/fuselibs-public,fusetools/fuselibs-public,fusetools/fuselibs-public,fusetools/fuselibs-public,fusetools/fuselibs-public,fusetools/fuselibs-public,fusetools/fuselibs-public