print the grid in terminal, modified based on PR #2

[LuxxxLucy]

Re-work #2 but take numpy array as input.

Example usage:

import arckit
import arckit.vis as vis

# Load the training data
train_set, eval_set = arckit.load_data()

# Get the first task
task = train_set[0]

# Loop through the training examples
for i, (input_array, output_array) in enumerate(task.train):
    print(f"Training Example {i+1}")
    print("Input:")
    vis.print_grid(input_array)
    print("Output:")
    vis.print_grid(output_array)
    print()

which has the same visual result as in #2