What you describe is how I tend to comment. At the opposite end of the spectrum we have Knuth's 'literate programming', exemplified in Tex, which has as its goal 'making programs more robust, more portable, more easily maintained, and arguably more fun' [0] by merging documentation with code. I'd bet if you counted documentation lines vs. code lines in Tex they'd be near 50/50, and I'd bet that if we asked Knuth whether the comment lines were supplemental he'd say no.

[0] https://www-cs-faculty.stanford.edu/~knuth/lp.html