attempt to resolve import statement in normal mode

[Songmu]

Hello. Thank you for providing a great plugin. I use it conveniently in my Go development.

This pull request is with feature suggestions. Feel free to reject it if it is not to your liking.

I created this patch because I wanted to immediately resolve that package name in import statements like import "github.com/path/to/pkg." Of course, I know there is a way to select in visual mode and then pull godoc. But I thought it would be more convenient to be able to open the package documentation right from normal mode.

What do you think?

[obcat]

Hello. Thank you for your request, it looks very useful!
It would be better if there is a check that the double-quoted string is a component of an import statement.
Is it possible to add such a check?

[Songmu]

It certainly seems convenient to be able to do that much. However, since import statements can span multiple lines, checking them seems a bit difficult with my vim scripting skills...
Any advice? Or is it realistically practical to leave it as is?

[obcat]

import statements can span multiple lines

Right, maybe covering all case is not easy...
Let me merge as-is and see if there are any problems.
Thank you for your contribution!