Can you clarify your belief that code isn't documentation? I'm far more familiar with the alternate philosophy that code is just another way humans communicate with each other (the computer doesn't care; the computer can take a machine-compatible binary from anywhere and execute it with no care as to whether humans understand the how or why of the program). Consider the "Literate programming" approach and tooling that operates in that paradigm (such as Jupyter notebooks).

Comments clearly aren't code, in the sense that they're a specific form in a language dedicated to being thrown out by the compiler / interpreter / etc (usually; I'm handwaving over the metaprogramming approaches like Doxygen that parse comments). But there's a reason we name variables `time_to_completion` instead of just `a`, or name functions (or have functions instead of jump pointers crammed into global variables), etc.