feat: bun package manager support

[jonlabelle]

Adds support for Bun package manager.

Closes #305

[Copilot]

Pull Request Overview

Adds support for the Bun package manager by letting the which() helper detect .bunx executables on Windows and streamlining the prettier lookup logic.

• Extend which() to include the .bunx extension for Bun executables on Windows
• Simplify make_local_prettier_path() by removing redundant .cmd handling

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
jsprettier/util.py	Append .bunx to PATHEXT so Windows which() can find Bun binaries
jsprettier/sthelper.py	Remove explicit .cmd extension handling and rely on which()

Comments suppressed due to low confidence (3)

jsprettier/util.py:308

• Add unit tests to ensure which() correctly resolves executables with the .bunx extension on Windows environments.

pathext.append(".bunx")  # add bunx extension for bun package manager

jsprettier/sthelper.py:196

• [nitpick] Update the surrounding comment to reflect that .cmd extension handling was removed and extension resolution is now delegated to which().

# 4. check globally install prettier

jsprettier/sthelper.py:197

• The import for ensure_file_has_ext is no longer used after removing the Windows .cmd logic—consider cleaning up the unused import.

return which('prettier')