Attempt to fix #134 is_feed called too early

[tomjn]

Description of the Change

This tries to fix a PHP warning that occurs when using the latest version, it is too early to call is_feed on the main query, but we don't need to, we're handed the query object on a silver platter so lets use that instead.

Closes #134

Alternate Designs

This seemed like the most straightforward way to fix it

Possible Drawbacks

¯\_(ツ)_/¯

Verification Process

None as of yet, just trying to be helpful and start the ball rolling by making the PR as quickly as possible

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Changelog Entry

Fixed - Bug fix for is_feed being called too early

Credits

Props @tomjn