Provide more intuitive error messages

[kkeri]

Several users, including me run into the same issue when attempting to use the extension. We get either command 'extension.generateStandalonePreview' not found or command 'extension.generateSidePreview' not found.

In fact the preconditions to executing these commands are precisely described.

• Open extension project from the root folder in vscode.
• Navigate to the manifest file for your extension (package.json for Visual Studio Code extensions and vss-extension.json for Team Services extensions).

In my case the extension project was not the root directory of the workspace. Yet I had hard time to figure out what happened. The error message suggests that there is some problem with the extension itself, hiding the real cause from the unaware user.

It would be very helpful to display more meaningful error messages. I think it would also be effective to place the Usage section in front of the screenshots in the readme file.

[nirmalapemireddy]

Thanks for your feedback about the documentation. We will update it accordingly.
Hope you are not facing issue in executing it now from the root folder

[kkeri]

Thanks. I was facing small issues but I found the right way to use the extension and indeed it is useful.