fix tests

Author: gwyneplaine

polaris-migrator/src/migrations/replace-sass-z-index/tests/replace-sass-z-index.output.scss

@@ -3,14 +3,14 @@ $someElement: (
 );
 
 .scenario-1 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: var(--p-z-1) + 1; */
   z-index: z-index(content) + 1;
   background-color: var(--p-background);
 }
 
 .scenario-2 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: var(--p-z-2) + 1; */
   z-index: z-index(overlay) + 1;
   background-color: var(--p-background);
@@ -27,14 +27,14 @@ $someElement: (
 }
 
 .scenario-5 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: map-get($someElement, someKey); */
   z-index: z-index(someKey, $someElement);
   background-color: var(--p-background);
 }
 
 .scenario-6 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: calc(var(--p-z-2) + var(--p-z-1)); */
   z-index: calc(z-index(overlay) + z-index(content));
 }

polaris-migrator/src/migrations/replace-sass-z-index/tests/with-namespace.output.scss

@@ -4,14 +4,14 @@ $someElement: (
 );
 
 .scenario-1 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: var(--p-z-1) + 1; */
   z-index: legacy-polaris-v8.z-index(content) + 1;
   background-color: var(--p-background);
 }
 
 .scenario-2 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: var(--p-z-2) + 1; */
   z-index: legacy-polaris-v8.z-index(overlay) + 1;
   background-color: var(--p-background);
@@ -28,14 +28,14 @@ $someElement: (
 }
 
 .scenario-5 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: map-get($someElement, someKey); */
   z-index: legacy-polaris-v8.z-index(someKey, $someElement);
   background-color: var(--p-background);
 }
 
 .scenario-6 {
-  /* polaris-migrator: This is a complex expression that we can't automatically convert. Please check this manually. */
+  /* polaris-migrator: Unable to migrate the following expression. Please upgrade manually. */
   /* z-index: calc(
     var(--p-z-2) + var(--p-z-1)
   ); */