Update READMEs and snippet outputs for v9

[eliperelman]

Fixes #1119.

[edmorley]

Similarly for yarn build:

ERROR in ./src/index.js
Module build failed (from ../neutrino/node_modules/eslint-loader/index.js):
Module failed because of a eslint error.
warning: Unexpected console statement (no-console) at src\index.js:7:3:
   5 | // This is needed for Hot Module Replacement
   6 | if (module.hot) {
>  7 |   console.log({hello});
     |   ^
   8 |   module.hot.accept();
   9 | }
  10 |


error: A space is required after '{' (babel/object-curly-spacing) at src\index.js:7:15:
   5 | // This is needed for Hot Module Replacement
   6 | if (module.hot) {
>  7 |   console.log({hello});
     |               ^
   8 |   module.hot.accept();
   9 | }
  10 |

...