Correct documentation for building web assembly form of libCellML.
Correct documentation for building web assembly form of libCellML.

nickerso/libcellml,hsorby/libcellml,hsorby/libcellml,nickerso/libcellml,hsorby/libcellml,cellml/libcellml,cellml/libcellml,nickerso/libcellml,hsorby/libcellml,nickerso/libcellml,cellml/libcellml,cellml/libcellml