fix: typo

Author: mashuai

src/parser.rs

@@ -919,7 +919,7 @@ impl Parser {
         } else if self.parse_keyword("INDEX") {
             ObjectType::Index
         } else {
-            return self.expected("TABLE ,VIEW or INDEX after DROP", self.peek_token());
+            return self.expected("TABLE, VIEW or INDEX after DROP", self.peek_token());
         };
         // Many dialects support the non standard `IF EXISTS` clause and allow
         // specifying multiple objects to delete in a single statement