title: Regex for matching whole words that contain dots
body: <p>In the following sentence:</p>
  
  <p><strong>I woke up in 5 p.m. today</strong></p>
  
  <p>I want to match the <strong>5 p.m.</strong>. 
  This pattern works:</p>
  
  <pre><code>5 p\.m\.
  </code></pre>
  
  <p>But I wanted it to match whole words only (so 5 p.m.us won't be matched).
  So I used this pattern:</p>
  
  <pre><code>\b5 p\.m\.\b
  </code></pre>
  
  <p>But this didn't work because of the dot. </p>
  
  <p>What will be the simplest regex to solve this? Can I define a zero-width match (\b style) that doesn't care if the character is a word character or not, only if it is a space or the end\beginning of the string?</p>