The general rule for acquiring locks on the prasing infrastructure and documents is to first lock the infrastructure and
then a document. This rule had to be reflected in several other API for example in Editor Indent API, which introduced a
concept of ExtraLock that API clients have to acquire prior using formatters/indenters and the SPI implementors are
obliged to bridge to the locking mechanism required by the backend infrastructure that they use for formatting/indenting
documents.

The infrastructure behind parsing is such a backend infrastructure, but its API does not allow to externally access its
lock. It's only possible to post task that run under the lock. We have to sort this our somehow otherwise it won't be
possible to use some of the editor API on top of the Parsing API.