In the notes, compiled the length error-checking step of `let-list-essence` and factored out the duplication logic into a new utility, compileDups().
In the notes, compiled the length error-checking step of `let-list-essence` and factored out the duplication logic into a new utility, compileDups().

era-platform/cene,rocketnia/era-cene,rocketnia/era,era-platform/cene,rocketnia/era-cene,rocketnia/era-cene,rocketnia/era,era-platform/cene,rocketnia/era