Amazon WorkSpaces Update: Added text to clarify case-sensitivity

Author: AWS

.changes/next-release/feature-AmazonWorkSpaces-9aebde8.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon WorkSpaces",
+    "contributor": "",
+    "description": "Added text to clarify case-sensitivity"
+}

services/workspaces/src/main/resources/codegen-resources/service-2.json

@@ -6749,7 +6749,7 @@
         },
         "UserName":{
           "shape":"UserName",
-          "documentation":"<p>The user name of the user for the WorkSpace. This user name must exist in the Directory Service directory for the WorkSpace.</p> <p>The reserved keyword, <code>[UNDEFINED]</code>, is used when creating user-decoupled WorkSpaces.</p>"
+          "documentation":"<p>The user name of the user for the WorkSpace. This user name must exist in the Directory Service directory for the WorkSpace.</p> <p>The username is not case-sensitive, but we recommend matching the case in the Directory Service directory to avoid potential incompatibilities.</p> <p>The reserved keyword, <code>[UNDEFINED]</code>, is used when creating user-decoupled WorkSpaces.</p>"
         },
         "BundleId":{
           "shape":"BundleId",