fix: remove template expression from result output description

A literal ${{ }} expression in action.yml is evaluated as a workflow
template at load time and fails with 'Unrecognized named-value: steps'.

Author: shenxianpeng

action.yml

@@ -39,7 +39,7 @@ inputs:
     default: false
 outputs:
   result:
-    description: Structured check results as JSON (status + per-scope checks). Consume with `${{ fromJSON(steps.<id>.outputs.result) }}`.
+    description: Structured check results as JSON (status + per-scope checks). Consume with fromJSON(steps.<id>.outputs.result).
 
 runs:
   using: "composite"