fix: Use scoped JSX namespace (#846)

Author: eps1lon

css.d.ts

@@ -1,3 +1,4 @@
+import type { JSX } from "react";
 // Definitions by: @types/styled-jsx <https://www.npmjs.com/package/@types/styled-jsx>
 
 declare module 'styled-jsx/css' {

index.d.ts

@@ -1,3 +1,4 @@
+import type { JSX } from "react";
 /// <reference types="./css" />
 /// <reference types="./macro" />
 /// <reference types="./style" />

macro.d.ts

@@ -1,3 +1,4 @@
+import type { JSX } from "react";
 declare module 'styled-jsx/macro' {
   namespace macro {
     function resolve(