Scala fixes

[josejuanmartinez]

Adds several "new" missing for non-class methods in Scala.

Description

When instantiating a class, we need to use new in Scala. This does not apply to pretrained(), because it's a class method.

Motivation and Context

There were some missing news that preventing the code to run properly due to missing new reserved word.

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Code improvements with no or little impact
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING page.
• I have added tests to cover my changes.
• All new and existing tests passed.