Enable 'strictNullChecks' in tsconfig samples, closes #1299

Author: Rel1cx

apps/website/content/docs/configuration/configure-project-config.mdx

@@ -28,6 +28,19 @@ The following rules require type information:
 - [`react-x/no-unused-props`](/docs/rules/no-unused-props)
 - [`react-x/prefer-read-only-props`](/docs/rules/prefer-read-only-props)
 
+<Callout type="warning">
+  Some rules, such as `react-x/no-leaked-conditional-rendering`, work better when certain TypeScript compiler options are enabled. We recommend enabling `strictNullChecks` in your `tsconfig.json` or `jsconfig.json`:
+
+  ```json
+  {
+    "compilerOptions": {
+      "strictNullChecks": true
+      // ...
+    }
+  }
+  ```
+</Callout>
+
 **The `project` or `projectService` options in `parserOptions` must be set correctly for the rules to work**.
 
 Enabling these rules **will have performance impact**, but they are more powerful than traditional lint rules.

apps/website/content/docs/getting-started/javascript.mdx

@@ -84,7 +84,8 @@ import { Step, Steps } from "fumadocs-ui/components/steps";
     {
       "compilerOptions": {
         // ...other options
-        "jsx": "react-jsx"
+        "jsx": "react-jsx",
+        "strictNullChecks": true // Recommended for better type inference
       },
       "include": ["**/*.js", "**/*.jsx"]
     }

apps/website/content/docs/getting-started/typescript.mdx

@@ -86,7 +86,8 @@ import { Step, Steps } from "fumadocs-ui/components/steps";
     {
       "compilerOptions": {
         // ...other options
-        "jsx": "react-jsx"
+        "jsx": "react-jsx",
+        "strictNullChecks": true // Recommended for better type inference
       },
       "include": ["**/*.ts", "**/*.tsx"]
     }