Fix ESLint warnings using 'yarn lint --fix'

Summary:
Hi! I would like to contribute to React Native, and I am just starting out. I forked the repo and found that it has quite a lot of ESLint warnings – many of which were automatically fixable. This PR is simply the result of running `yarn lint --fix` from the root folder.

Most changes are removing trailing spaces from comments.

Haven't really done any manual testing, since I haven't done any code changes manually. `yarn test` runs fine, `yarn flow` runs fine, `yarn prettier` is satisfied.

N/A

[INTERNAL][MINOR][] - Fix ESLint warnings
Closes https://github.com/facebook/react-native/pull/18047

Differential Revision: D7054948

Pulled By: hramos

fbshipit-source-id: d53e692698d1687de5821c3fb5cdb76a5e03b71e

flow-github/metro.js

@@ -21,4 +21,4 @@ declare module 'metro/src/HmrServer' {
 
 declare module 'metro/src/lib/bundle-modules/HMRClient' {
   declare module.exports: any;
-}
+}