add a comment to describe the ERS/ERI histaux_wav2med_file1_ntperfile change

Author: alperaltuntas

cime_config/namelist_definition_drv.xml

@@ -2182,6 +2182,8 @@
     <desc>Number of time samples per file.</desc>
     <values>
       <value>30</value>
+      <!-- Generate daily WW3 hist files for ERS/ERI tests to prevent mismatched filenames
+        and contents between initial and restart runs.-->
       <value TESTCASE='ERS'>1</value>
       <value TESTCASE='ERI'>1</value>
     </values>