Extension to keep annotations on arbitrary keywords

I’ve looked through the VSCode extension store and other random searches but have been unable to find what I’m looking for. Before I dive into learning to write my own extension…

I am looking for a VSCode extension that will let me add keywords and custom annotations for those keywords in my code. In my head, specific words will be highlighted/underlined, and a small pop up will display notes that I have previously set for that keyword.

The primary use case is to remind me on specific use case or implications of particular keywords. For instance, if I use the default HTTP client in Golang, I’d like to be reminded that there is no default timeout.

The definition would look something like:

“definitions”: [  
    {
      “text”: “http.Get”,
      “comment”: “the default go http client does not have a timeout.”
    }
]

Upon adding this line to my code

*resp, err := http.Get("http://example.com/")

would highlight/underline http.Get and when I mouseover, I will get a custom reminder that “the default http client does not have a timeout.”