Add line endings and printf debugging section

[RyanCavanaugh]

Let's help the robot help itself

[Copilot]

Pull Request Overview

This PR refines the Copilot guide by renaming the title, adding a new debugging tips section, and reminding contributors to verify line endings.

• Renames the document header for brevity
• Introduces a “Debugging Tips” section with console.log patterns
• Adds a reminder to ensure consistent CRLF line endings

Comments suppressed due to low confidence (3)

.github/copilot-instructions.md:1

• [nitpick] The new document title is quite generic; consider refining it to reflect the guide’s focus on TypeScript test writing and compiler tests to maintain clarity.

# Guide for Copilot

.github/copilot-instructions.md:287

• [nitpick] The code fence language specifier ts,diff may not render correctly in Markdown; consider using a standard ts code fence and marking diffs separately for clarity.

```ts,diff

.github/copilot-instructions.md:327

• The indentation for this bullet appears misaligned, creating an extra nesting level. Align it with the other bullets under “Always format and lint” for consistent formatting.

   - Double-check your line endings. Source files in this repo typically use CRLF line endings. Fix all line endings to be consistent before you wrap up

[jakebailey]

it's annoying that "run the formatter" is not sufficient here

[rubiesonthesky]

Are the line endings something that can’t be changed to be same in all files? Or set in gitattributes? You probably would have done it already if it was easy 😅

I know that this document is for Copilot but it’s kinda handy for human developers too. :)

[RyanCavanaugh]

We don't set line endings in .gitattributes because we need to have tests that have differing line endings

[jakebailey]

.gitattributes works like a .gitignore, so theoretically we could scope it, but I don't know how it'll play with things like autocrlf.

[jakebailey]

That being said, it seems like practically all tooling wants to emit LF, not CRLF (duh), but switching every file over to LF will probably ruin git blame. But maybe the ignore file can handle that kind of change.