Toggle CodeView and fullscreen from the API

These APIs still map directly to the underlying modules. fullscreen.isFullscreen returns the current fullscreen state, while codeview.toggle swaps between WYSIWYG and HTML editing.

Try switching between rich text and HTML, then enter fullscreen and ask the API for the current state.

Mode output
Ready.
Example configuration - View Modes
summernote.create('#view-modes-editor', {
  height: 260,
  toolbar: [
    ['view', ['codeview', 'fullscreen']],
    ['history', ['undo', 'redo']],
  ],
});

summernote.invoke('#view-modes-editor', 'codeview.toggle');
summernote.invoke('#view-modes-editor', 'fullscreen.toggle');
const fullscreen = summernote.invoke('#view-modes-editor', 'fullscreen.isFullscreen');