Feat: accounting notation for fmt_number(), fmt_percent(), fmt_integer() and fmt_currency()

[rich-iannone]

This introduces the accounting= arg to fmt_number(), fmt_percent(), fmt_integer() and fmt_currency(), allowing for accounting notation (e.g., "-343.27" -> "(343.27)". This new functionality also extends to the same formatters in the vals module.

Here is an example table demonstrating usage:

from great_tables import GT
import polars as pl

df = pl.DataFrame(
    {"number": [-1.2, 23.6], "percent": [-0.0523, 0.363], "integer": [2323, -23213], "currency": [-24334.23, 7323.253]}
).with_columns(number_acc = pl.col("number"), percent_acc = pl.col("percent"), integer_acc = pl.col("integer"), currency_acc = pl.col("currency"))

(
    GT(df)
    .fmt_number(columns="number")
    .fmt_percent(columns="percent")
    .fmt_integer(columns="integer")
    .fmt_currency(columns="currency")
    .fmt_number(columns="number_acc", accounting=True)
    .fmt_percent(columns="percent_acc", accounting=True)
    .fmt_integer(columns="integer_acc", accounting=True)
    .fmt_currency(columns="currency_acc", accounting=True)
    .tab_spanner(label="Default formatting", columns=[0, 1, 2, 3])
    .tab_spanner(label="Accounting notation", columns=[4, 5, 6, 7])
)

Fixes: #278

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.81%. Comparing base (925fa41) to head (dd05ed7).

Files with missing lines	Patch %	Lines
great_tables/_formats.py	94.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #513      +/-   ##
==========================================
+ Coverage   89.79%   89.81%   +0.01%     
==========================================
  Files          45       45              
  Lines        5321     5331      +10     
==========================================
+ Hits         4778     4788      +10     
  Misses        543      543              

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[machow]

I left one suggestion for a minor tweak to the docstring language, but feel free to take or leave it! (not the language is repeated in several places)

[machow]

WDYT of changing these docstrings to something like "Whether to use accounting style, which wraps negative numbers in parentheses instead of using a minus sign."

[rich-iannone]

Sounds good, now done!

[machow]

It seems like this is not testing that fmt_integer uses accounting format on negative numbers

[rich-iannone]

The first four columns of this table are formatted but with accounting=False (minus signs persist) , the last four have accounting=True so we do get the negative values in parens there.