Slight nit, but I don't think it's accurate to say that Go has an "officially supported and stable release of an Intellij IDE". While Gogland is excellent (I use it as my main Go editor at work), I think it's still technically in pre-release.
On a more unrelated note, is Groovy widely used? As someone who doesn't really ever use JVM languages, my impression was that it didn't have the similar usage to Kotlin and Scala, although I might be mistaken.
Apache Groovy's used for scripting on the JVM, like Bash and Perl on Linux. It's OK for glue code, mock testing, and 10-line build scripts in Gradle. But 5 years ago, some of Groovy's backers tried to re-purpose it as a competitor to statically typed languages like Java, Kotlin, and Scala, which is when things went awry. If it had stuck to its knitting, it could have been used widely for scripting classes written in Kotlin and Scala as well as Java. But it didn't even keep up with Java -- it doesn't even have Java 8's lambdas on the eve of Java 9's release.
On a more unrelated note, is Groovy widely used? As someone who doesn't really ever use JVM languages, my impression was that it didn't have the similar usage to Kotlin and Scala, although I might be mistaken.