Update the change file comment to match styling (#210)

# Pull Request

## 📖 Description

<!--- Provide some background and a description of your work. -->
Small text update to correct the grammar expected for the change files.

change/@microsoft-fast-tooling-9393ac54-a66d-4ff6-a080-3eb47ca4d209.json

@@ -1,6 +1,6 @@
 {
   "type": "patch",
-  "comment": "adding file extensions to import and export paths",
+  "comment": "Added file extensions to import and export paths",
   "packageName": "@microsoft/fast-tooling",
   "email": "nicholasrice@users.noreply.github.com",
   "dependentChangeType": "patch"