Fix various typos in aggregation doc (apache#12301)

datafusion/expr-common/src/groups_accumulator.rs

@@ -29,7 +29,7 @@ pub enum EmitTo {
     /// indexes down by `n`.
     ///
     /// For example, if `n=10`, group_index `0, 1, ... 9` are emitted
-    /// and group indexes '`10, 11, 12, ...` become `0, 1, 2, ...`.
+    /// and group indexes `10, 11, 12, ...` become `0, 1, 2, ...`.
     First(usize),
 }
 
@@ -113,7 +113,7 @@ pub trait GroupsAccumulator: Send {
     /// each group, and `evaluate` will produce that running sum as
     /// its output for all groups, in group_index order
     ///
-    /// If `emit_to`` is [`EmitTo::All`], the accumulator should
+    /// If `emit_to` is [`EmitTo::All`], the accumulator should
     /// return all groups and release / reset its internal state
     /// equivalent to when it was first created.
     ///

datafusion/physical-plan/src/aggregates/mod.rs

@@ -1006,7 +1006,8 @@ pub fn get_finer_aggregate_exprs_requirement(
     Ok(PhysicalSortRequirement::from_sort_exprs(&requirement))
 }
 
-/// returns physical expressions for arguments to evaluate against a batch
+/// Returns physical expressions for arguments to evaluate against a batch.
+///
 /// The expressions are different depending on `mode`:
 /// * Partial: AggregateFunctionExpr::expressions
 /// * Final: columns of `AggregateFunctionExpr::state_fields()`

datafusion/physical-plan/src/aggregates/order/full.rs

@@ -21,7 +21,7 @@ use datafusion_expr::EmitTo;
 /// group keys
 ///
 /// When the group values are sorted, as soon as we see group `n+1` we
-/// know we will never see any rows for group `n again and thus they
+/// know we will never see any rows for group `n` again and thus they
 /// can be emitted.
 ///
 /// For example, given `SUM(amt) GROUP BY id` if the input is sorted
@@ -63,7 +63,7 @@ enum State {
     /// Seen no input yet
     Start,
 
-    /// Data is in progress. `current is the current group for which
+    /// Data is in progress. `current` is the current group for which
     /// values are being generated. Can emit `current` - 1
     InProgress { current: usize },
 

datafusion/physical-plan/src/aggregates/order/partial.rs

@@ -32,7 +32,7 @@ use std::sync::Arc;
 /// key and earlier.
 ///
 /// For example, given `SUM(amt) GROUP BY id, state` if the input is
-/// sorted by `state, when a new value of `state` is seen, all groups
+/// sorted by `state`, when a new value of `state` is seen, all groups
 /// with prior values of `state` can be emitted.
 ///
 /// The state is tracked like this:

datafusion/physical-plan/src/aggregates/row_hash.rs

@@ -95,7 +95,7 @@ struct SpillState {
     // ========================================================================
     // STATES:
     // Fields changes during execution. Can be buffer, or state flags that
-    // influence the exeuction in parent `GroupedHashAggregateStream`
+    // influence the execution in parent `GroupedHashAggregateStream`
     // ========================================================================
     /// If data has previously been spilled, the locations of the
     /// spill files (in Arrow IPC format)