Documentation for addTelemetryInitializer is unclear

Nobody has claimed this yet.

I am trying to use addTelemetryInitializer as per the documentation but it is unclear because the docs (API-reference.md) refer to:
```
window.appInsights = appInsights;

// Add telemetry initializer
appInsights.trackPageView();
```
but the JS code from the portal does not look like that, it looks like this:
```
var sdkInstance="appInsightsSDK";window[sdkInstance]="appInsights";var etc...
{
instrumentationKey:"key"
}); window[aiName] = aisdk,aisdk.queue && aisdk.queue.length ===0 && aisdk.trackPageView({});;
```
I tried splitting the last line and ended up with
```
}); window[aiName];
// Add my initializer here
aisdk.queue && aisdk.trackPageView({});
```
But this doesn't seem to work. The initializer is not called and I cannot see the call to track in the network monitor. Is there some more clear documentation about how this works with the new JS snippet?

Start with API-reference.md and compare its window.appInsights example with the JavaScript snippet generated by the portal. Clarify how addTelemetryInitializer and trackPageView relate to the snippet, including where an initializer belongs. Done means the documentation gives a working, unambiguous example for the portal-generated setup.

Written by the indexing model from the issue text.