Mark beta presets in ESLint React docs

Author: Rel1cx

apps/website/content/docs/presets.mdx

@@ -19,7 +19,7 @@ The following presets are available in `@eslint-react/eslint-plugin`:
   Enforce rules that are recommended by ESLint React for general purpose React + React DOM projects.\
   _This preset includes the `x`, `dom`, and `web-api` presets._
 
-- `strict`\
+- `strict` (beta)\
   Same as the `recommended` preset but enables additional strict rules.
 
 ## TypeScript Specialized
@@ -30,10 +30,10 @@ The following presets are available in `@eslint-react/eslint-plugin`:
 - `recommended-type-checked`\
   Same as the `recommended-typescript` preset but enables additional rules that require type information.
 
-- `strict-typescript`\
+- `strict-typescript` (beta)\
   Same as the `strict` preset but disables rules that can be enforced by TypeScript.
 
-- `strict-type-checked`\
+- `strict-type-checked` (beta)\
   Same as the `strict-typescript` preset but enables additional rules that require type information.
 
 ### Combined (beta)