Initial proposed implementation for handling almost-good fishing holes.

[armele]

Closes #10008

Changes proposed in this pull request

• Change assessment of pond quality from binary to trinary - introducing a "suboptimal" pond, which may appear to a player to be valid, bit is not (because of underwater flowing water instead of water source blocks).
• The fisher will give a notification (pasted below) about the quality of the pond, including location and guidance on how to repair it.

Testing

• [X] Yes I tested this before submitting it.
• [ No] I also did a multiplayer test.

Review please