TestComplete script code (unit.js, etc) are plain text files, editable and readable within any standard text editor. There is no direct integration with TestComplete for a tool like javadocs, however, if you point the tool at the directories and tell it to read js files, it should work as it does for any other development environment.
Why automate? I do automated testing because there's only so much a human being can do and remain healthy. Sleep is a requirement. So, while people sleep, automation that I create does what I've described above in order to make sure that nothing gets past the final defense of the testing group. I love good food, good books, good friends, and good fun.