The KEYWORDS tag, which must be placed inside a
        RULES tag and can only appear once, specifies a list
        of keywords to highlight. Keywords are similar to
        SEQs, except that SEQs match
        anywhere in the text, whereas keywords only match whole words. Words are
        considered to be runs of text separated by non-alphanumeric
        characters.
The KEYWORDS tag does not define any
        attributes.
Each child element of the KEYWORDS tag is an
        element whose name is a token type, and whose content is the keyword to
        highlight. For example, the following rule highlights the most common
        Java keywords:
<KEYWORDS> <KEYWORD1>if</KEYWORD1> <KEYWORD1>else</KEYWORD1> <KEYWORD3>int</KEYWORD3> <KEYWORD3>void</KEYWORD3> </KEYWORDS>