Some renames

Summary:
Some non-semantic changes. Mostly an earlier rename that was accidentally done only locally rather than across the codebase

Also support `.spec` test extension, which is more idiomatic Jest, since we don't use the `.node` and `.electron` distinction anymore anyway.

Reviewed By: jknoxville

Differential Revision: D22976438

fbshipit-source-id: f3abedb36cbac1e835295177117ccbca492a67a1

desktop/flipper-plugin/src/index.ts

@@ -10,10 +10,7 @@
 import './plugin/PluginBase';
 import * as TestUtilites from './test-utils/test-utils';
 
-export {
-  SandyPluginInstance,
-  PluginClient as FlipperClient,
-} from './plugin/Plugin';
+export {SandyPluginInstance, PluginClient} from './plugin/Plugin';
 export {
   Device,
   DeviceLogEntry,