FWIW, my note taking app is github. Created a private repo, keeping my notes as "issues". I can label, link, search them, insert images, add comments etc. Can someone name a relevant feature that is missing from github?
Every time I want to memorize something, I either open an issue against my fake repo (created specifically for this purpose) or add another comment to an existing issue. It's a good idea to create 1 issue per topic and just keep adding separate comments. Cross-references can be added for the linked concepts. Github markdown is quite rich. There are features (like "<details>") that can be found only there. There's not much to say actually. Try it out - you will figure out what works best for you.
