Replace double whitespaces with single once in the custom store warning message (#1199)

Author: pvorona

src/components/connectAdvanced.js

@@ -76,9 +76,9 @@ export default function connectAdvanced(
   )
 
   const customStoreWarningMessage =
-    'To use a custom Redux store for specific components,  create a custom React context with ' +
+    'To use a custom Redux store for specific components, create a custom React context with ' +
     "React.createContext(), and pass the context object to React Redux's Provider and specific components" +
-    ' like:  <Provider context={MyContext}><ConnectedComponent context={MyContext} /></Provider>. ' +
+    ' like: <Provider context={MyContext}><ConnectedComponent context={MyContext} /></Provider>. ' +
     'You may also pass a {context : MyContext} option to connect'
 
   invariant(