Description

#12056 added support for default and type-checked arguments in do closures.

This PR adds examples for those features. It also:

• Fixes the TODO (a closure parameter that wasn't being used) that was preventing a result from being added
• Removes extraneous commas from the descriptions
• Adds an example demonstrating multiple positional closure arguments

User-Facing Changes

Help examples only

Tests + Formatting

• 🟢 toolkit fmt
• 🟢 toolkit clippy
• 🟢 toolkit test
• 🟢 toolkit test stdlib

After Submitting