IntelliJ IDEA: Jump from interface to implementing method in Go

No, such shortcut doesn't exist.

You can use "Find Usage" to determine where the specific interface method is used, but if you want to see all the concrete implementations the current way is to search the entire project for the method name.

This support has been added in Goland (or with go plugin in IntelliJ ultimate) now. Shortcut for the same is Alt+Cmd+B (Option+Cmd+B for Mac).