php8: fixed a bug with # comments

[i582]

Example from issue:

<?php
#
# Comment
#

$a = 100;

The problem with the example from the issue is that # is immediately followed by a line break.
And since the rule in the lexer for such comments was changed, this case was handled incorrectly.

(('#' ^'[') | '//') any_line* when is_not_comment_end => {
   lex.ungetStr("?>")
   lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
};

This rule has one problem, it checks two characters at once, first for the match #, and
then for the mismatch [, which leads to the fact that in the case of an empty comment, the first
matcher will capture #, and the second line break (\n), which will lead to the fact that any_line
matcher will not work and will not increase the line number.

The next rule added is specifically for this case.

'#' newline when is_not_comment_end => {
    lex.ungetStr("?>")
    lex.addFreeFloatingToken(tkn, token.T_COMMENT, lex.ts, lex.te)
};

Fixes #21