Sugar cane can be placed underwater

The Bug:

Sugar cane can be placed underwater.

If there is water adjacent to and below the desired location of placement, sugar cane can be placed. This of course results in sugar cane being allowed to be placed underwater.

Steps to Reproduce:

1. Obtain some sugar cane and locate an open body of water.
2. Attempt to place sugar cane on any block underwater that has water adjacent to and below it.
3. Take note as to whether or not sugar cane can be placed underwater.

Observed Behavior:

Sugar cane can be placed underwater.

Expected Behavior:

Sugar cane would not be able to be placed underwater.

Code Analysis:

Code analysis by [Mod] Avoma can be found in this comment.