message: update README.md
  expose SeverityLevel enum in snippet
diff: @@ -59,7 +59,7 @@ If your app does not use NPM, you can directly instrument your webpages with App
  ```html
  <script type="text/javascript">
  -var sdkInstance="appInsightsSDK";window[sdkInstance]="appInsights";var aiName=window[sdkInstance],aisdk=window[aiName]||function(e){function n(e){t[e]=function(){var n=arguments;t.queue.push(function(){t[e].apply(t,n)})}}var t={config:e};t.initialize=!0;var i=document,a=window;setTimeout(function(){var n=i.createElement("script");n.src=e.url||"https://az416426.vo.msecnd.net/scripts/b/ai.2.min.js",i.getElementsByTagName("script")[0].parentNode.appendChild(n)});try{t.cookie=i.cookie}catch(e){}t.queue=[],t.version=2;for(var r=["Event","PageView","Exception","Trace","DependencyData","Metric","PageViewPerformance"];r.length;)n("track"+r.pop());n("startTrackPage"),n("stopTrackPage");var s="Track"+r[0];if(n("start"+s),n("stop"+s),n("addTelemetryInitializer"),n("setAuthenticatedUserContext"),n("clearAuthenticatedUserContext"),n("flush"),!(!0===e.disableExceptionTracking||e.extensionConfig&&e.extensionConfig.ApplicationInsightsAnalytics&&!0===e.extensionConfig.ApplicationInsightsAnalytics.disableExceptionTracking)){n("_"+(r="onerror"));var o=a[r];a[r]=function(e,n,i,a,s){var c=o&&o(e,n,i,a,s);return!0!==c&&t["_"+r]({message:e,url:n,lineNumber:i,columnNumber:a,error:s}),c},e.autoExceptionInstrumented=!0}return t}(
  +var sdkInstance="appInsightsSDK";window[sdkInstance]="appInsights";var aiName=window[sdkInstance],aisdk=window[aiName]||function(e){function n(e){t[e]=function(){var n=arguments;t.queue.push(function(){t[e].apply(t,n)})}}var t={config:e};t.initialize=!0;var i=document,a=window;setTimeout(function(){var n=i.createElement("script");n.src=e.url||"https://az416426.vo.msecnd.net/scripts/b/ai.2.min.js",i.getElementsByTagName("script")[0].parentNode.appendChild(n)});try{t.cookie=i.cookie}catch(e){}t.queue=[],t.version=2;for(var r=["Event","PageView","Exception","Trace","DependencyData","Metric","PageViewPerformance"];r.length;)n("track"+r.pop());n("startTrackPage"),n("stopTrackPage");var s="Track"+r[0];if(n("start"+s),n("stop"+s),n("addTelemetryInitializer"),n("setAuthenticatedUserContext"),n("clearAuthenticatedUserContext"),n("flush"),t.SeverityLevel={Verbose:0,Information:1,Warning:2,Error:3,Critical:4},!(!0===e.disableExceptionTracking||e.extensionConfig&&e.extensionConfig.ApplicationInsightsAnalytics&&!0===e.extensionConfig.ApplicationInsightsAnalytics.disableExceptionTracking)){n("_"+(r="onerror"));var o=a[r];a[r]=function(e,n,i,a,s){var c=o&&o(e,n,i,a,s);return!0!==c&&t["_"+r]({message:e,url:n,lineNumber:i,columnNumber:a,error:s}),c},e.autoExceptionInstrumented=!0}return t}(
  {
  instrumentationKey:"INSTRUMENTATION_KEY"
  }
  