Missing Core Classes for Completion

[JoelProminic]

While I was testing #47 today, I noticed that code completion wasn't suggesting some common classes from the Java libraries. I could reproduce this behavior with Moonshine 3.3.0 and Grails 3.3.10 (Groovy 2.4.17) as well:

1. Create a new Grails project
2. Create a new Groovy file at src/main/groovy/TestGroovy.groovy
3. In the TestGroovy() method, type "StringBuilde" and press CTRL-Space
4. BUG: I expected this to find StringBuilder, which is a Java class with Groovy modifications

I could also reproduce this with plain Java classes like ArrayList and Vector. New Groovy classes like GString or XmlSlurper complete properly.

If I type out a StringBuilder initialization, I find that tooltips and method completion work fine.

[JoelProminic]

This is working well for me in the latest Moonshine build. I tested some other classes as well, and I haven't found anything missing so far.

I added a bug entry to the Moonshine-IDE changelog to track this.