Creates an extension that enables or disables languageData
-based autocompletion.
Returns a CodeMirror 6 extension that registers the given CompletionSource.
Use this extension rather than the built-in CodeMirror autocompletion
if you don't want to use languageData-based autocompletion.
Using autocompletion({ override: [ ... ]})
causes errors when done by multiple plugins.
extension
should be a CodeMirror 6 extension.
Points to a CodeMirror 6 EditorView instance.