FIx playground link for matching arithmetic expressions. (#790)

Author: vivster7

website/advanced/pattern-parse.md

@@ -256,7 +256,7 @@ rule:
     # pattern: $OP
 ```
 
-See the above rule to match all arithmetic expressions in [action](/playground.html#eyJtb2RlIjoiQ29uZmlnIiwibGFuZyI6ImphdmFzY3JpcHQiLCJxdWVyeSI6ImNvbnNvbGUubG9nKCQkJCkiLCJyZXdyaXRlIjoiIiwic3RyaWN0bmVzcyI6InNpZ25hdHVyZSIsInNlbGVjdG9yIjoiY2FsbF9leHByZXNzaW9uIiwiY29uZmlnIjoicnVsZTpcbiAgcGF0dGVybjpcbiAgICBjb250ZXh0OiBjb25zb2xlLmxvZygkJCQpXG4gICAgc2VsZWN0b3I6IGV4cHJlc3Npb25fc3RhdGVtZW50XG5maXg6ICcnIiwic291cmNlIjoiY29uc29sZS5sb2coZm9vKVxuY29uc29sZS5sb2coYmFyKTsifQ==).
+See the above rule to match all arithmetic expressions in [action](/playground.html#eyJtb2RlIjoiQ29uZmlnIiwibGFuZyI6ImphdmFzY3JpcHQiLCJxdWVyeSI6ImNvbnNvbGUubG9nKCQkJCkiLCJyZXdyaXRlIjoiIiwic3RyaWN0bmVzcyI6InNpZ25hdHVyZSIsInNlbGVjdG9yIjoiY2FsbF9leHByZXNzaW9uIiwiY29uZmlnIjoicnVsZTpcbiAga2luZDogYmluYXJ5X2V4cHJlc3Npb25cbiAgaGFzOlxuICAgIGZpZWxkOiBvcGVyYXRvclxuICAgIHBhdHRlcm46ICQkT1BcbiAgICAjIHBhdHRlcm46ICRPUCIsInNvdXJjZSI6IjEgKyAxIn0=).
 
 ### How Multi Meta Variables Match Code
 
@@ -272,4 +272,4 @@ ast-grep playground is a great tool to debug pattern code. The pattern tab and p
 
 ![playground](/image/pattern-debugger.jpg)
 
-In next article, we will explain how ast-grep's pattern is used to match code, the pattern matching algorithm.
+In next article, we will explain how ast-grep's pattern is used to match code, the pattern matching algorithm.