Remove FlowFixMe's from TypeScript

Summary: This diff was a joy to draft.

Reviewed By: jknoxville

Differential Revision: D17344676

fbshipit-source-id: 0694d0393fa243edef61408ecfee92912fbbfa32

src/utils/isProduction.tsx

@@ -8,7 +8,6 @@
 import electron from 'electron';
 
 const _isProduction = !/node_modules[\\/]electron[\\/]/.test(
-  // $FlowFixMe: execPath exists, but is not in electron API spec
   process.execPath || electron.remote.process.execPath,
 );