Update documentation of trusted types' data to reflect a page may use…

… enforcing and reporting mode

Fixes mikewest#5

index.html

@@ -85,8 +85,8 @@ <h2 id="trusted-types">
     <p>
       The data below is gathered from
       <a href="https://chromestatus.com/metrics/feature/popularity">Chrome's usage statistics</a>,
-      and represents the percentage of Chrome page loads that use Trusted Types in either enforcing
-      or reporting mode, and of those, which enforce Trusted Types.
+      and represents the percentage of Chrome page loads that use Trusted Types in enforcing or
+      reporting mode or both, only in enforcing mode and only in reporting mode.
     </p>
 
     <canvas id="tt_usage"></canvas>