feat!: Added the ability to merge cells with Merge.LEFT

[DenverCoder1]

Resolves #59

Example usage

from table2ascii import table2ascii, Merge

output = table2ascii(
    body=[
        ["A", "B", "C", "D"],
        ["E", "Long cell", Merge.LEFT, Merge.LEFT],
    ],
)

print(output)

Test with pip install -U git+https://github.com/DenverCoder1/table2ascii.git@merge