params = DidChangeTextDocumentParams docId (List changeEvents)
newVFS <- liftIO $ changeVFS oldVFS (fmClientDidChangeTextDocumentNotification params)
modify (\s -> s { vfs = newVFS })
params = DidChangeTextDocumentParams docId (List changeEvents)
newVFS <- liftIO $ changeVFS oldVFS (fmClientDidChangeTextDocumentNotification params)
modify (\s -> s { vfs = newVFS })