chore(ResliceCursorWidget): fix example

[Jo-Byr]

Context

Some examples have been broken since the switch to lil-gui, the example of ResliceCursorWidget is one of them. The widgets were displayed below a white div.

Results

The example is now correctly displayed.

Changes

Added a container element, by taking inspiration from DepthTest example.

PR and Code Checklist

• semantic-release commit messages
• Run npm run reformat to have correctly formatted code

Testing

Tested with

npm run build
npm run docs:generate
npm run docs:build
npm run docs:build-examples
npm run docs:serve 

[finetjul]

Can you please explain what the problem is/was ?

[Jo-Byr]

Can you please explain what the problem is/was ?

I don't know why this fixes the problem.

As explained in the top comment, I noticed the example's content was present in the page, but under a blank div. I searched for a working example with a similar structure (one that uses document.createElement), which is DepthTest, and tested it.

[daker]

@Jo-Byr just remove the div with id "vtk-root" it was not used

https://github.com/Kitware/vtk-js/blob/master/Documentation/scripts/build-examples.mjs#L66

[finetjul]

You also need to remove it from that example code that references 'vtk-root'.

[finetjul]

LGTM.

Please edit your PR opening comment.