Fences Should Connect to Shelf Blocks Despite Shelf is Non-Full Block

Fences currently connect to shelf block's front face in an unexpected way, forming visual connections even though shelves are non-full blocks.

Note: Normally, fences should not connect across empty space to partial blocks like trapdoors. But this behavior actually provides useful building possibilities, and its preservation as an intentional feature would benefit builders. I report this bug to prevent others report again. Actually I hope this issue is work as intended.

How to Reproduce:

1. Place a shelf block.

2. Place a fence block directly against the shelf's front face.

3. Observe that the fence visually connects to the shelf despite the shelf's non-full block shape.

Observed Result:

The fence connects to the shelf as if it were a full block, creating an attached post effect.

Expected Result:

The fence should not connect to the shelf like trapdoors.

(However, this behavior is worth keeping as a feature for better building flexibility.)