Attach instead of start dev server and documentation updates

Summary:
^

Instead of 'start' use 'attach' as it seems closer to what the function actually does.

Reviewed By: passy

Differential Revision: D36310846

fbshipit-source-id: db90efc6ec3207b1a5a38139a3ba01d2f7d2aebd

desktop/flipper-server/src/startFlipperServer.tsx

@@ -25,6 +25,15 @@ import {
 import path from 'path';
 import fs from 'fs-extra';
 
+/**
+ * Creates an instance of FlipperServer (FlipperServerImpl). This is the
+ * server used by clients to connect to.
+ * @param rootDir Application path.
+ * @param staticPath Static assets path.
+ * @param settingsString Optional settings used to override defaults.
+ * @param enableLauncherSettings Optional launcher settings used to override defaults.
+ * @returns
+ */
 export async function startFlipperServer(
   rootDir: string,
   staticPath: string,
@@ -81,7 +90,7 @@ export async function startFlipperServer(
     {
       environmentInfo,
       env: parseEnvironmentVariables(process.env),
-      // TODO: make userame parameterizable
+      // TODO: make username parameterizable
       gatekeepers: getGatekeepers(environmentInfo.os.unixname),
       paths: {
         appPath,