Footnotes with rST------------------[#c]_..note::[#d]_[#a]_..[#a] some footnote *text*..[#b] a footnote before its reference
[#b]_..[#c] a footnote referenced first
..[#d] a footnote referenced in a directive
[#123]_[#123]_..[#123] multiple references footnote
..[#x] an unreferenced footnote