AnalyserModel: slight update to the isValid() documentation.
AnalyserModel: slight update to the isValid() documentation.

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