use `localhost` instead of `127.0.0.1` in examples

[argshook]

in This PR:

• format example code with prettier
• use localhost instead of 127.0.0.1 in examples

The example code is used in other code bases to showcase how this client should be used.

It is also used with examples.manifest.yaml, which describes examples with interpolatable values.

In particular, the examples.manifest.yaml has these:

  addr:
    host: localhost
    port: 9009

when example code like ./examples/basic.js is interpolated with values from examples.manifest.yaml, the host part is missed.

Thus, we should be consistent and in both examples.manifest.yaml and examples/*.js use as host either:

1. localhost or
2. 127.0.0.1

This PR chooses localhost