That's a fair question... ultimately it's possible to get something similar using other tools, but IMO it won't be as easy. Just as a contrived example with a simple query:
https://gothrough.dev/search?q=writer
https://github.com/search?q=repo%3Agolang%2Fgo+writer&type=c...
The problem I really wanted to solve for myself was primarily discovery for standard interfaces. I don't write Go code as regularly as I'd like and don't have code review from a professional setting.
Also if you are using goland (not everyone is i know thats why i pointed it out as second argument) you have the complete standard-lib lookup ready via the IDE.
Maybe im missing something and this is usefull but im coding go for several years now and dont see the point