Update v16.1.5 release notes for config.anal update

- update the release notes to mention the change made to config.anal
- config.anal was updated to support correct global info files for
retrospective experiments

Refs: #439,#489

docs/Release_Notes.gfs.v16.1.5.txt

@@ -73,7 +73,8 @@ FIX CHANGES
 
 PARM/CONFIG CHANGES
 
-* No change from GFS v16.1.4
+* config.anal
+  * update global_convinfo.txt notes and global_satinfo.txt if-blocks for retrospective dates; no operational impact
 
 JOBS CHANGES