suggestion: ability to prioritize blocks found while tunneling

similar to #mine: `#tunnel `
then baritone will tunnel and if it sees one of the blocks specified, it will prioritize it and return to tunneling once it found it

Start by tracing the existing `#tunnel ` command and how tunneling chooses targets. Determine where blocks encountered during tunneling could be prioritized, then define behavior for returning to the original tunnel after each target is found. The issue does not name files or tests, so the relevant entry points and validation coverage must first be located.

Written by the indexing model from the issue text.