Unignore gradle-wrapper.properties. For context, see docs: https://docs.gradle.org/current/userguide/gradle_wrapper.html#sec:wrapper_generation

The workaround for https://youtrack.jetbrains.com/issue/IDEA-116898 is fixed now, so we can remove the workaround.

If you have a Java package with `build` in it, the current version will always ignore files in that directory.
This change makes it so only the root "build" directory is ignored.

I believe that this assumes .gitignore is in the root of a project.

This is added because .jar files are usually ignored (see Java.gitignore)

Update Gradle.gitignore