message: Update test-plan.md
  Include some new Razor scenarios.
diff: @@ -106,6 +106,9 @@ To setup a test project to verify on you can do:
  * Completion is available for types that exist in the project (i.e. `Program`)
  * Typing `@model DateTime` prompts for completion for the `model` symbol and the `DateTime` symbol.
  +#### C# Lightbulbs
  +* Typing `@{ var x = new HtmlString("sdf"); }`results in squiggles under `HtmlString`. Selecting `HtmlString` and pressing Ctrl+. results in a change suggestion to fully-qualify that type name as `Microsoft.AspNetCore.Html.HtmlString`. Hitting enter on that suggestion resolves the squiggles and changes the line.
  +
  ##### C# Signature Help
  * Typing `@Html.Raw()` prompts for signature help inside of the `()`.
  @@ -137,6 +140,9 @@ To setup a test project to verify on you can do:
  ##### C# Diagnostics
  * Typing `@ThisDoesNotExist` results in an error being created and squiggled in the .cshtml file. NOTE: This error squiggly will be misaligned due to known issues.
  +#### TagHelper Quick Info
  +* Typing `<environment></environment>` then hovering the mouse over the opening tag results in an informative window about that TagHelper.
  +
  ##### TagHelper completion
  Note that the pipe in the below examples indicates the cursor.
  * Typing `<environment>` prompts you with HTML completion for the `environment` tag and on completion commit auto-completes the closing tag.
  