Update format string in test package by updating generated RcppExports file

[eddelbuettel]

@kalibera found another format string in need of an update, this time in an embedded source package used by tinytest, and very kindly emailed a diff.

The fix was actually even more trivial thanks to #1288 as it needed simply an call of compileAttributes() with the update source package from #1288. This also updates two other minor aspects in the generated code we had addressed since the test example was first created.

Checklist

• Code compiles correctly
• R CMD check still passes all tests
• Preferably, new tests were added which fail without the change
• Document the changes by file in ChangeLog

[Enchufa2]

LGTM!