hub: improve search() API documentation
    
    Reformat this text to match Sphinx's conventions. This makes it easier
    for developers to read this documentation.
    
    There are a couple small corrections here as well:
    
    - matchType accepts more values than "glob" or "regex", and it treats
      any other value as a plain "=" (strict string match).
    
    - Only globs and regexes are searched insensitively