Fix File Type Factory for libsonnet

[rubencougil]

With this fix, both jsonnet and libsonnet are working within the plugin.
Built and tested locally (with IntelliJ 2021.1.1)

[bryant1410]

I wonder why this is needed. With semicolon it should work:

https://github.com/JetBrains/intellij-community/blob/cefe3d90e0d1371f05a7555e3fdbdcef2c70c647/platform/platform-api/src/com/intellij/openapi/fileTypes/FileTypeConsumer.java#L14

libsonnet is not working as it is_

[rubencougil]

I wonder why this is needed. With semicolon it should work:

https://github.com/JetBrains/intellij-community/blob/cefe3d90e0d1371f05a7555e3fdbdcef2c70c647/platform/platform-api/src/com/intellij/openapi/fileTypes/FileTypeConsumer.java#L14

libsonnet is not working as it is_

Yep, according to the doc it should work, but it doesn't.