Minor: make some physical_optimizer rules public (#11171)

This patch makes public some physical_optimizer submodules. This allows
external code to use optimizations passes from these submodules.

datafusion/core/src/physical_optimizer/mod.rs

@@ -31,12 +31,12 @@ pub mod limited_distinct_aggregation;
 pub mod optimizer;
 pub mod output_requirements;
 pub mod pipeline_checker;
-mod projection_pushdown;
+pub mod projection_pushdown;
 pub mod pruning;
 pub mod replace_with_order_preserving_variants;
 mod sort_pushdown;
 pub mod topk_aggregation;
-mod update_aggr_exprs;
+pub mod update_aggr_exprs;
 mod utils;
 
 #[cfg(test)]

datafusion/core/src/physical_optimizer/update_aggr_exprs.rs

@@ -52,6 +52,7 @@ use datafusion_physical_plan::{
 pub struct OptimizeAggregateOrder {}
 
 impl OptimizeAggregateOrder {
+    #[allow(missing_docs)]
     pub fn new() -> Self {
         Self::default()
     }