AnalyserModel: added some background information to the `areEquivalentVariables()` method.
AnalyserModel: added some background information to the `areEquivalentVariables()` method.

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