Override documentation URL

[matt0x6F]

Feature Request
We run our own internal GoDoc. Being able to point at that instead of pkg.go.dev would make this package usable in our GoDoc.

What's currently happening
Clicking a node yields documentation for pkg.go.dev which only serves public packages

What you want to happen
Be able to override the pkg.go.dev URL.

[matt0x6F]

If you let me know the desired argument name I can implement this.

[egonelbre]

I've been thinking a good name for this and thoughts about them:

1. -link - is clear that it's linking something, but at the same time is harder to understand that this is where you replace the documentation server url.
2. -href - matches the dot format, however isn't quite clear in what it does.
3. -docs - is clear in the usage, but might be too specific for the needs. e.g. it wouldn't necessarily have to be a documentation server that the nodes link to. It could also link to github or something completely different.
4. -docs-url - feels verbose and similar issues as 3.

Similarly the question is whether there's a need for customization in how it links. As an example, labels allow a template as the argument.

Based on this, I would think -docs is probably the clearest in purpose and usage. Also won't make it difficult to use something more complicated in the future.