docs(README): Explain example phpcs.xml.dist config file

    phpcbf --standard=Drupal /file/to/drupal/example_module

## Store settings in a phpcs.xml.dist file

In order to save and commit your PHPCS settings to Git you can use a

phpcs.xml.dist file in your project like this:

```xml

<?xml version="1.0" encoding="UTF-8"?>

<ruleset name="myproject">

  <description>PHP CodeSniffer configuration for myproject development.</description>

  <!-- Check all files in the current directory and below. -->

  <file>.</file>

  <arg name="extensions" value="php,module,inc,install,test,profile,theme,css,info,txt,md"/>

  <!-- Change this value to 7 if you want to check Drupal 7 code. -->

  <config name="drupal_core_version" value="8"/>

  <!-- If you have Coder installed locally then you can reference the Drupal

  standards with relative paths. Otherwise simply use "Drupal" and

  "DrupalPractice. -->

  <rule ref="../vendor/drupal/coder/coder_sniffer/Drupal"/>

  <rule ref="../vendor/drupal/coder/coder_sniffer/DrupalPractice"/>

  <!-- Example how you would disable a rule you do not like:

  <rule ref="PEAR.Functions.ValidDefaultValue.NotAtEnd">

    <severity>0</severity>

  </rule>

  -->

</ruleset>

```

Then you can invoke phpcs without any options and it will read phpcs.xml.dist

from the current directory. This can also be useful for Continues Integration

setups.

## Working with Editors

Drupal Code Sniffer can be used with various editors.