Update account linking error copy

Author: catarak

client/modules/IDE/components/ErrorModal.jsx

@@ -18,8 +18,8 @@ class ErrorModal extends React.Component {
   oauthError() {
     return (
       <p>
-        {'There was an error linking your GitHub account. This account has already been linked'}
-        {' to another account.'}
+        {'There was a problem linking your GitHub account to your p5.js Web Editor account.'}
+        {' Your GitHub account has already been linked to another p5.js Web Editor account.'}
       </p>
     );
   }

client/modules/User/pages/AccountView.jsx

@@ -73,7 +73,7 @@ class AccountView extends React.Component {
         {showError &&
           <Overlay
             title="Error Linking Account"
-            ariaLabel="OAuth Error"
+            ariaLabel="Error Lnking Account"
             closeOverlay={() => {
               browserHistory.push(this.props.location.pathname);
             }}