title: Returning first letter of NSString capitalized
body: <p>I would like to return the first letter of an <code>NSString</code> capitalized. I have an <code>UISearchDisplayController</code> that displays section titles according to the title of the search results. </p>
  
  <pre><code>- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
      NSString *sectionTitle;
      if (searching) 
          sectionTitle = [searchSectionTitles objectAtIndex:section];
      else
          sectionTitle = [[collation sectionTitles] objectAtIndex:section];
  
      return sectionTitle;
  
  }
  </code></pre>
  
  <p>And to return the letter, in my search function,</p>
  
  <pre><code>[searchSectionTitles addObject:[lastName firstLetter]];
  </code></pre>
  
  <p>How can I make </p>
  
  <pre><code>- (NSString *)firstLetter
  </code></pre>
  
  <p>return the first letter of an <code>NSString</code>? </p>