Update hs upload --clean flag description

lang/en.lyaml

@@ -972,7 +972,7 @@ en:
         convertFields:
           describe: "If true, converts any javascript fields files contained in module folder or project root."
         clean:
-          describe: "Will cause upload to delete files in your HubSpot account that are not found locally."
+          describe: "Will delete the destination directory and its contents before uploading. This will also clear the global content associated with any global partial templates and modules."
         force:
           describe: "Skips confirmation prompts when doing a clean upload."
       previewUrl: "To preview this theme, visit: {{ previewUrl }}"