Clarify that locale is not an imported variable (#2833)

Author: snowystinger

packages/dev/docs/pages/react-spectrum/ssr.mdx

@@ -34,7 +34,7 @@ In order to make React Spectrum components work with SSR, you will need to wrap
 import {SSRProvider, Provider, defaultTheme} from '@adobe/react-spectrum';
 
 <SSRProvider>
-  <Provider theme={defaultTheme} locale={locale}>
+  <Provider theme={defaultTheme} locale={yourLocaleHere}>
     <App />
   </Provider>
 </SSRProvider>