Feature Request: Please add "is_returns" flag for monthly_heatmap_detailedview

[BlackArbsCEO]

when using qs._plotting.core.monthly_heatmap_detailedview it assumes that the data that is passed is in the form of prices. But there are many times where we don't have the "prices" but instead the strategy returns. It would be useful if we could tell the function if the data is in price form and needs conversion to returns or if it is already in daily return format. I give a quick and dirty example below that I did in my local version.

def monthly_heatmap_detailedview(
        returns,
        is_daily_returns=False,
        grayscale=False,
        figsize=(14, 6),
        annot_size=11,
        returns_label="Strategy",
        fontname="Arial",
        monthly_dd_font_rate=0.8,
        annual_dd_font_rate=0.8,
        return_font_rate=1.0,
        savefig=None,
        show=True,
):
    if is_daily_returns:
        daily_returns = returns.copy()
    else:
        daily_returns = returns.pct_change(fill_method=None).fillna(0)
    monthly_returns = daily_returns.resample('ME').apply(lambda x: (x + 1).prod() - 1) * 100
    monthly_drawdowns = calculate_monthly_drawdowns(returns) * 100

    monthly_combined = _pd.DataFrame({
        "Returns": monthly_returns,
        "Drawdowns": monthly_drawdowns
    })

    #...rest of function...