Use normal comma separation when displaying index columns

The column list in `CREATE INDEX` now matches the style used elsewhere,
e.g. in `TableConstraint`, which is to use spaces after commas.

```sql
-- before:
CREATE INDEX idx_name ON table_name (column1,column2,column3);
-- after:
CREATE INDEX idx_name ON table_name (column1, column2, column3);
```

When `CreateIndex` was added, there was no explanation for the lack of
spaces, so I assume it was just author preference. But standard style in
all documentation I've seen is to use spaces after commas (including
[MSSQL]'s documentation of `INCLUDE`, which copied the no-spaces style
when added).

[MSSQL]: https://learn.microsoft.com/en-us/sql/t-sql/statements/create-index-transact-sql?view=sql-server-ver17#i-create-an-index-with-included-non-key-columns

Author: mvzink

src/ast/dml.rs

@@ -106,9 +106,9 @@ impl Display for CreateIndex {
         if let Some(value) = &self.using {
             write!(f, " USING {value} ")?;
         }
-        write!(f, "({})", display_separated(&self.columns, ","))?;
+        write!(f, "({})", display_comma_separated(&self.columns))?;
         if !self.include.is_empty() {
-            write!(f, " INCLUDE ({})", display_separated(&self.include, ","))?;
+            write!(f, " INCLUDE ({})", display_comma_separated(&self.include))?;
         }
         if let Some(value) = self.nulls_distinct {
             if value {

tests/sqlparser_common.rs

@@ -9175,7 +9175,7 @@ fn ensure_multiple_dialects_are_tested() {
 
 #[test]
 fn parse_create_index() {
-    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test(name,age DESC)";
+    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test(name, age DESC)";
     let indexed_columns: Vec<IndexColumn> = vec![
         IndexColumn {
             operator_class: None,
@@ -9221,7 +9221,7 @@ fn parse_create_index() {
 
 #[test]
 fn test_create_index_with_using_function() {
-    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test USING BTREE (name,age DESC)";
+    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test USING BTREE (name, age DESC)";
     let indexed_columns: Vec<IndexColumn> = vec![
         IndexColumn {
             operator_class: None,

tests/sqlparser_postgres.rs

@@ -2486,7 +2486,7 @@ fn parse_array_multi_subscript() {
 
 #[test]
 fn parse_create_index() {
-    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1,col2)";
+    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1, col2)";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2517,7 +2517,7 @@ fn parse_create_index() {
 
 #[test]
 fn parse_create_anonymous_index() {
-    let sql = "CREATE INDEX ON my_table(col1,col2)";
+    let sql = "CREATE INDEX ON my_table(col1, col2)";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name,
@@ -2577,7 +2577,7 @@ fn parse_create_indices_with_operator_classes() {
                     .unwrap_or_default()
             );
             let multi_column_sql_statement = format!(
-                "CREATE INDEX the_index_name ON users USING {expected_index_type} (column_name,concat_users_name(first_name, last_name){})",
+                "CREATE INDEX the_index_name ON users USING {expected_index_type} (column_name, concat_users_name(first_name, last_name){})",
                 expected_operator_class.as_ref().map(|oc| format!(" {oc}"))
                     .unwrap_or_default()
             );
@@ -2698,7 +2698,7 @@ fn parse_create_indices_with_operator_classes() {
 #[test]
 fn parse_create_bloom() {
     let sql =
-        "CREATE INDEX bloomidx ON tbloom USING BLOOM (i1,i2,i3) WITH (length = 80, col1 = 2, col2 = 2, col3 = 4)";
+        "CREATE INDEX bloomidx ON tbloom USING BLOOM (i1, i2, i3) WITH (length = 80, col1 = 2, col2 = 2, col3 = 4)";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2813,7 +2813,7 @@ fn parse_create_table_with_empty_inherits_fails() {
 
 #[test]
 fn parse_create_index_concurrently() {
-    let sql = "CREATE INDEX CONCURRENTLY IF NOT EXISTS my_index ON my_table(col1,col2)";
+    let sql = "CREATE INDEX CONCURRENTLY IF NOT EXISTS my_index ON my_table(col1, col2)";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2844,7 +2844,7 @@ fn parse_create_index_concurrently() {
 
 #[test]
 fn parse_create_index_with_predicate() {
-    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1,col2) WHERE col3 IS NULL";
+    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1, col2) WHERE col3 IS NULL";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2875,7 +2875,7 @@ fn parse_create_index_with_predicate() {
 
 #[test]
 fn parse_create_index_with_include() {
-    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1,col2) INCLUDE (col3)";
+    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1, col2) INCLUDE (col3)";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2906,7 +2906,7 @@ fn parse_create_index_with_include() {
 
 #[test]
 fn parse_create_index_with_nulls_distinct() {
-    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1,col2) NULLS NOT DISTINCT";
+    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1, col2) NULLS NOT DISTINCT";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),
@@ -2935,7 +2935,7 @@ fn parse_create_index_with_nulls_distinct() {
         _ => unreachable!(),
     }
 
-    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1,col2) NULLS DISTINCT";
+    let sql = "CREATE INDEX IF NOT EXISTS my_index ON my_table(col1, col2) NULLS DISTINCT";
     match pg().verified_stmt(sql) {
         Statement::CreateIndex(CreateIndex {
             name: Some(ObjectName(name)),