Fix unused variable warning

Rescue exception is assigned to `e`, but it is never used.
This leads to a warning:

```
rspec-parameterized-core-2.0.0/lib/rspec/parameterized/core/composite_parser.rb:28: warning: assigned but unused variable - e
```

Author: viralpraxis

lib/rspec/parameterized/core/composite_parser.rb

@@ -25,7 +25,7 @@ def self.use_prism?
         # @raise [RSpec::Parameterized::Core::ParserSyntaxError]
         def self.to_raw_source_with_parser(obj)
           obj.is_a?(Proc) ? obj.to_raw_source : obj.inspect
-        rescue Parser::SyntaxError => e
+        rescue Parser::SyntaxError
           raise ParserSyntaxError
         end
         private_class_method :to_raw_source_with_parser