Count wildcard alias (#14927)

* fix alias

* append the string

* window count

* add column

* fmt

* rm todo

* fixed partitioned

* fix test

* update doc

* Suggestion to reduce API surface area

---------

Co-authored-by: Andrew Lamb <[email protected]>

Author: jayzhan211

datafusion/core/tests/dataframe/dataframe_functions.rs

@@ -1145,9 +1145,9 @@ async fn test_count_wildcard() -> Result<()> {
         .build()
         .unwrap();
 
-    let expected = "Sort: count(Int64(1)) ASC NULLS LAST [count(Int64(1)):Int64]\
-    \n  Projection: count(Int64(1)) [count(Int64(1)):Int64]\
-    \n    Aggregate: groupBy=[[test.b]], aggr=[[count(Int64(1))]] [b:UInt32, count(Int64(1)):Int64]\
+    let expected = "Sort: count(*) ASC NULLS LAST [count(*):Int64]\
+    \n  Projection: count(*) [count(*):Int64]\
+    \n    Aggregate: groupBy=[[test.b]], aggr=[[count(Int64(1)) AS count(*)]] [b:UInt32, count(*):Int64]\
     \n      TableScan: test [a:UInt32, b:UInt32, c:UInt32]";
 
     let formatted_plan = plan.display_indent_schema().to_string();