Release v0.20.0

Bug Fixes

• Disable indentation of JSExp in the formatter for now (be57054)
• Make listCtorSpread not mutate the input List (eb22e9f)
• Make ImportNotFound work for local imports (ddae32f)
• Various fixes (ccafe79)

Features

• Add multiline code for the REPL (fcb0b00)
• Add ppInspect, cInspect, ppLog, and cLog (b83d256)
• Add ppTrace and cTrace (c348dce)
• Basic draft of the REPL (f9d413f)
• Great progress on the REPL (a8144ba)
• Make type aliases be able to reference types or aliases defined later (b7f2d59)