fix: snowflake double quote escape

Author: danedmunds

pegjs/snowflake.pegjs

@@ -4239,6 +4239,7 @@ escape_char
     }
   / "\\" { return "\\"; }
   / "''" { return "''" }
+  / '""' { return '""' }
 
 line_terminator
   = [\n\r]

test/snowflake.spec.js

@@ -525,6 +525,20 @@ describe('snowflake', () => {
         'SELECT "a" + "b" FROM DUAL'
       ]
     },
+    {
+      title: 'escape double quoted',
+      sql: [
+        'SELECT "foo""bar"',
+        'SELECT "foo""bar"'
+      ]
+    },
+    {
+      title: 'escape double quoted twice',
+      sql: [
+        'SELECT "my ""column"""',
+        'SELECT "my ""column"""'
+      ]
+    },
   ]
   SQL_LIST.forEach(sqlInfo => {
     const { title, sql } = sqlInfo