v6.4.0-alpha.19

Features

• Controls: Don't set arg in validateOptions if it would be undefined (#15654)
• Vue: Add support for tsx (#11936)

Bug Fixes

• CLI: Fix trailing comma handling for "-s" command line paramenter (#15615)
• Components: Lazy-load syntax highlighter (#15607)

Maintenance

• Controls: Clean up arg unboxing and switch statements (#14394)
• Examples: Fix react-ts to be runnable standalone (#15621)