v6.1.0-alpha.21

Features

• Sidebar: Better search, keyboard shortcuts, and "recently viewed" (#12601)
• Source-loader: Generate sourcemaps (#12277)
• Core: Add apng support (#12639)

Bug Fixes

• Addon-docs: Fix Memo React components in ArgsTable (#12686)
• Core: Fix babel-loader path resolution (#12536)

Maintenance

• Core: Log which CSF file is failing to load (#12690)
• Build: Speed up CI checks (#12315)