Add conditional SwiftSyntaxMacroExpansion import for dependency entry macro file

[KaiOelfke]

Description

Most PF library macro files have this:

#if !canImport(SwiftSyntax600)
  import SwiftSyntaxMacroExpansion
#endif

But DependencyEntryMacro.swift doesn't have it. I am getting a compile error:

Cannot find 'MacroExpansionErrorMessage' in scope

I guess I can try to upgrade the version of Swift Syntax I use. This is with Xcode 26.6.0 RC. But it felt suspicious that this is inconsistent with other library code.

Checklist

• I have determined whether this bug is also reproducible in a vanilla SwiftUI project.
• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

No response

Actual behavior

No response

Steps to reproduce

No response

Dependencies version information

1.13.0

Destination operating system

iOS 26

Xcode version information

26.6.0

Swift Compiler version information

[stephencelis]

@KaiOelfke You down to PR a fix?

[KaiOelfke]

@KaiOelfke You down to PR a fix?

Sorry been too busy. I added one now. I removed some outdated package so my app is now using a newer swift syntax.