fix: update messages for 'react-x/jsx-no-iife' and 'react-x/jsx-uses-vars' rules (#1127)

Author: Rel1cx

packages/plugins/eslint-plugin-react-x/src/rules/jsx-no-iife.ts

@@ -22,7 +22,7 @@ export default createRule<[], MessageID>({
       [Symbol.for("rule_features")]: RULE_FEATURES,
     },
     messages: {
-      jsxNoIife: "",
+      jsxNoIife: "Avoid using IIFE in JSX elements.",
     },
     schema: [],
   },

packages/plugins/eslint-plugin-react-x/src/rules/jsx-uses-vars.ts

@@ -19,7 +19,7 @@ export default createRule<[], MessageID>({
       [Symbol.for("rule_features")]: RULE_FEATURES,
     },
     messages: {
-      jsxUsesVars: "",
+      jsxUsesVars: "An identifier in JSX is marked as used.",
     },
     schema: [],
   },