Enhance documentation by adding argument descriptions to functions in historic_vol, pivots, reduce_df, and update_df modules

src/panel/historic_vol.rs

@@ -248,7 +248,7 @@ fn get_period_indices(
 }
 
 /// Calculate historic volatility.
-/// Arguments:
+/// # Arguments:
 /// - `df`: A Quantamental DataFrame.
 /// - `xcat`: The category to calculate the historic volatility for.
 /// - `cids`: A list of cross-sections. If none are provided, all cross-sections available

src/panel/mod.rs

@@ -1,3 +1,3 @@
 pub mod historic_vol;
-
+pub mod linear_composite;