rxode2 cmt/linear and other interp interaction

[mattfidler]

message(rxode2::rxNorm(rxode2::rxModelVars("cmt(a);\nlocf(b);d/dt(a)=b*kel")))
#> cmt(a);
#> locfcmt(a)(b);
#> d/dt(a)=b*kel;

^{Created on 2024-08-10 with reprex v2.1.1}

locfcmt(a)(b) is not valid syntax and it should be locf(b)