Add a ph tag for Chrome Cleanup to the description guidelines

Change-Id: Idf8027acd402ce8faf8095370688ea8f33f46fa7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2551513Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Chris Sharp <csharp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829653}

docs/enterprise/description_guidelines.md

@@ -4,6 +4,7 @@ how various product names and the like should be referenced.
 * Chrome: `<ph name="PRODUCT_NAME">$1<ex>Google Chrome</ex></ph>`
 * Chrome OS: `<ph name="PRODUCT_OS_NAME">$2<ex>Google Chrome OS</ex></ph>`
 * Chrome Browser Cloud Management: `<ph name="CHROME_BROWSER_CLOUD_MANAGEMENT_NAME">Chrome Browser Cloud Management</ph>`
+* Chrome Cleanup: `<ph name="CHROME_CLEANUP_NAME">Chrome Cleanup</ph>`
 * Linux: `<ph name="LINUX_OS_NAME">Linux</ph>`
 * Internet Explorer: `<ph name="IE_PRODUCT_NAME">Internet® Explorer®</ph>`
 * Google Admin console: `<ph name="GOOGLE_ADMIN_CONSOLE_PRODUCT_NAME">Google Admin console</ph>`