Renamed the "accounting.report.utils.period_choosers" module to "accounting.report.utils.period_chooser", because there is only period chooser now.

src/accounting/report/utils/period_chooser.py

@@ -14,7 +14,7 @@
 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
-"""The period choosers.
+"""The period chooser.
 
 This file is largely taken from the NanoParma ERP project, first written in
 2021/9/16 by imacat (imacat@nanoparma.com).