Consider removing the "Block #" labelling

[patrickmj]

When looking at blocks on a page, they get a heading like "Block 1", "Block 2", etc.

But, someone else editing the page and reordering makes those unstable. It's possible for one day Block 1 to become Block 2. Doesn't matter too much in the interface, but outside the interface if someone thinks "Block 1 has this content", "Block 2 has that content", that could get disrupted. Seems like that info is duplicative of simple display order?

Especially with the new checks on conflicting edits, might make sense to simplify to just the block type info, without the Block 1, Block 2 info.