Fix/basic suggestion (#119)

* fix: correct suggetion logic in multiple sql case

* test: add multiple sql test case of suggestion

* feat: export SyntaxContextType as enum

test/parser/flinksql/suggestion/fixtures/multipleSql.sql

@@ -0,0 +1,19 @@
+CREATE TABLE orders (
+    order_uid  BIGINT,
+    product_id BIGINT,
+    price      DECIMAL(32, 2),
+    order_time TIMESTAMP(3)
+) WITH (
+    'connector' = 'datagen'
+);
+
+CREATE TABLE orders (
+    order_uid  BIGINT,
+    product_id BIGINT,
+    price      DECIMAL(32, 2),
+    order_time TIMESTAMP(3)
+) WITH (
+    'connector' = 'datagen'
+);
+
+use cat1.