title: Can't highlight the same text within NSString using TTTAttributedLabel
body: <p>I'm new in iOS development and I'm trying to highlight a repetitive text inside a NSString using TTTAttributedLabel but always I obtain the first occurrence bolded. This is a little sample i'm using, what I'm doing wrong?. I'm not sure if the library is prepared to this kind of functionality.</p>
  
  <pre><code>UIView *viewOfSection1 = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 1700)];
  viewOfSection1.backgroundColor = [UIColor whiteColor];
  KMSection *section1 = [[KMSection alloc] init];
  section1.view = viewOfSection1;
  section1.title = @"Some Title";
  section1.colorForBackground = [UIColor whiteColor];
  
  TTTAttributedLabel *label = [[TTTAttributedLabel alloc] initWithFrame:CGRectMake(0, 0, 300, 1700)];
  label.font = [UIFont systemFontOfSize:14];
  label.textColor = [UIColor darkGrayColor];
  label.lineBreakMode = LINE_BREAK_WORD_WRAP;
  label.numberOfLines = 0;
  label.textAlignment = NSTextAlignmentJustified;
  [label setTextInsets:UIEdgeInsetsMake(0, 40, 0, 7)];
  
  NSString *text = @"This is text sample , text sample"
  
  [label setText:text afterInheritingLabelAttributesAndConfiguringWithBlock:^ NSMutableAttributedString *(NSMutableAttributedString *mutableAttributedString) {
      NSRange boldRange = [[mutableAttributedString string] rangeOfString:@"text," options:NSCaseInsensitiveSearch];
      NSRange boldRange1 = [[mutableAttributedString string] rangeOfString:@"sample" options:NSCaseInsensitiveSearch];
  
      UIFont *boldSystemFont = [UIFont boldSystemFontOfSize:14];
      CTFontRef font = CTFontCreateWithName((__bridge CFStringRef)boldSystemFont.fontName, boldSystemFont.pointSize, NULL);
      if (font) {
          [mutableAttributedString addAttribute:(NSString *)kCTFontAttributeName value:(__bridge id)font range:boldRange];
          [mutableAttributedString addAttribute:(NSString *)kCTFontAttributeName value:(__bridge id)font range:boldRange1];
          CFRelease(font);
      }
  
      return mutableAttributedString;
  }];
  
  [viewOfSection1 addSubview:label];
  
  return @[section1];
  </code></pre>
  
  <p>The only way to perform what I'm looking for, was to separate the text in two parts and highlights the text separately.</p>
  
  <p>Thanks in advanced.</p>