Move `toolbar` => `Toolbar`

src/annotator/components/test/toolbar-test.js → src/annotator/components/test/Toolbar-test.js

 import { mount } from 'enzyme';
 
-import Toolbar from '../toolbar';
+import Toolbar from '../Toolbar';
 
 import { checkAccessibility } from '../../../test-util/accessibility';
 

src/annotator/test/toolbar-test.js

@@ -20,7 +20,7 @@ describe('ToolbarController', () => {
     };
 
     $imports.$mock({
-      './components/toolbar': FakeToolbar,
+      './components/Toolbar': FakeToolbar,
     });
   });
 

src/annotator/toolbar.js

 import { createRef, render } from 'preact';
 
-import Toolbar from './components/toolbar';
+import Toolbar from './components/Toolbar';
 
 /**
  * @typedef ToolbarOptions