Detect and auto fix the superfluous naming of the variable in the variable docblock

I've tried the new VariableComment sniff on our codebase and it turned up a large number of instances where developers had mistakenly declared the variable name in the docblock, like this:

  /**
   * The current user.
   *
   * @var \Drupal\Core\Session\AccountProxyInterface $user
   */
  protected $user;

This presumably happens by copy-pasting from a parameter docblock, or by sheer muscle memory.

The current warning that the sniff is throwing is a little bit confusing:

Expected "\Drupal\Core\Session\AccountProxyInterfaceuser" but found "\Drupal\Core\Session\AccountProxyInterface $user" for @var tag in member variable comment

Let's provide a helpful warning + an auto fixer for this common mistake.