Generic/SpreadOperatorSpacingAfter: move parse error test to its own file

[biinari]

Description

Suggested changelog entry

N/A

Related issues/external references

See #143

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  • This change is only breaking for integrators, not for external standards or end-users.
• Documentation improvement

PR checklist

• I have checked there is no other PR open for the same change.
• I have read the Contribution Guidelines.
• I grant the project the right to include and distribute the code under the BSD-3-Clause license (and I have the right to grant these rights).
• I have added tests to cover my changes.
• I have verified that the code complies with the projects coding standards.
• [Required for new sniffs] I have added XML documentation for the sniff.

[jrfnl]

💯 I'll merge this once the build has passed.
Thanks for contributing @biinari!

[biinari]

Thanks @jrfnl. I have a couple more on their way for tonight (I started with comments that indicated they needed to be the last in the file).

[jrfnl]

@biinari That's awesome! I may not get to them all tonight, but will review those tomorrow in that case. Thanks for your willingness to help the project!