Handle SYNC keyword token in KILL QUERY parsing

- SYNC is a keyword token, not just IDENT
- Check for both token types when parsing SYNC/ASYNC modifiers

Fixes 02792_drop_projection_lwd/stmt6 and 2 other tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: kyleconroy

parser/parser.go

@@ -8268,7 +8268,8 @@ func (p *Parser) parseKill() *ast.KillQuery {
 	}
 
 	// Parse SYNC/ASYNC/TEST
-	for p.currentIs(token.IDENT) {
+	// SYNC can be a keyword token or IDENT
+	for p.currentIs(token.IDENT) || p.currentIs(token.SYNC) {
 		upper := strings.ToUpper(p.current.Value)
 		switch upper {
 		case "SYNC":

parser/testdata/02597_column_update_tricky_expression_and_replication/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt8": true
-  }
-}
+{}

parser/testdata/02792_drop_projection_lwd/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt6": true
-  }
-}
+{}

parser/testdata/03640_multiple_mutations_with_error_with_rewrite_parts/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt7": true
-  }
-}
+{}