ensureSyntaxTree
Get the syntax tree for the state if it covers at least up to position upto. In Kodemirror's synchronous parsing model, the tree always covers the full document, so this always returns the tree when one is available.
Return
The syntax tree, or null if no language is configured.
Parameters
upto
The minimum document position the tree must cover.
timeout
Ignored in the synchronous parsing model. Present for API compatibility with upstream CodeMirror.