Replace uses of @code in Javascript documentation with Markdown backticks

Rosie CL for []/third_party (local approval/rejection).

[]
b/71392935
Tested:
    TAP --sample for global presubmit queue
    []

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=184412611

java/google/registry/ui/js/session.js

@@ -118,7 +118,7 @@ registry.Session.PARSER_BREAKER_ = ')]}\'\n';
 
 
 /**
- * Displays {@code message} to user in bloody butterbar.
+ * Displays `message` to user in bloody butterbar.
  * @param {string} message
  * @private
  */