A new lexer command: Less

[massaad]

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It will be helpful if we can do some look-ahead while in the lexer without tying the grammar to a particular target language.

So, I am proposing adding a new lexer command that is almost the opposite of more. Using an example derived from the example in the book (in section 12.4):

SPECIAL_OPEN : '<?' Name -> less, pushMode(PROC_INSTR);

when matched, will switch to PROC_INSTR mode, but then will start matching again starting from <?.