When the tokenizer encounters a keyword, it sniffs whether the
last non-whitespace character before it happens to be a '.' and
if it is, the keyword is assumed to be the second part of a
qualified name.
Thus, before this commit
-- blah.
UPDATE ...
would not be parsed as KEYWORD (UPDATE) followed by stuff, but as
an ID (blah.UPDATE) followed by stuff.
With this change, newlines are no longer counted as whitespace.