Blazor Debugging Launch.json url property documentation

[TanayParikh]

Fixes: dotnet/aspnetcore#38382

[guardrex]

@TanayParikh ... Check my grammar/style update to confirm that I didn't shift the meaning.

[guardrex]

btw @TanayParikh ... This is confusing. Why is this configurable? If the dev changes it, it doesn't launch at the right page/tab? ... then are they supposed to navigate to what they set this to manually by typing the URL they set for url into the browser's address bar? Nevermind ... I think I get it now.

[guardrex]

Ok ... maybe I get it. 😄 ... It's just saying that if this doesn't match where the app is configured to load (URL) then they'll get the about:blank. They need to match for it to open and debug at the right URL. 🤔

[TanayParikh]

btw @TanayParikh ... This is confusing. Why is this configurable? If the dev changes it, it doesn't launch at the right page/tab? ... then are they supposed to navigate to what they set this to manually by typing the URL they set for url into the browser's address bar?

This url is used to launch the browser. The default is localhost:5001. If there's nothing at localhost:5001 then the browser opens the about:blank page. This can occur if the user changed the Properties/launchSettings.json to have a different application url. This behavior is documented in the blazor/tooling page.

Examine the Properties/launchSettings.json file and determine the URL of the app from the applicationUrl property (for example, https://localhost:7268). Note this value for use in the launch.json file.

In the launch configuration of the .vscode/launch.json file:

Set the current working directory (cwd) to the Server project folder.
Indicate the app's URL with the url property. Use the value recorded earlier from the Properties/launchSettings.json file.