title: stringr: find rows where any column content matches a regex
body: <p>Consider the following example</p>
  
  <pre><code>&gt; data_text &lt;- data.frame(text = c('where', 'are', 'you'),
                          blob = c('little', 'nice', 'text'))
  &gt; data_text
  # A tibble: 3 x 2
     text   blob
    &lt;chr&gt;  &lt;chr&gt;
  1 where little
  2   are   nice
  3   you   text
  </code></pre>
  
  <p>I want to print the rows that contain the regex <code>text</code> (that is, row 3)</p>
  
  <p>Problem is, I have hundreds of columns and I dont know which one contains this string. <code>str_detect</code> only work with one column at a time...</p>
  
  <p>How can I do that using the <code>stringr</code> package?
  Thanks!</p>