Expand error messages: print symbol names, parentheses and shift tokens,
and negative shift counts.

Fix error messages: print "Division" instead of "Divide"; print
multiplier-like, addition-like and logical operator tokens instead of
garbage (usually the command name).

ddb has a primitive lexer with excessive information hiding that makes
it hard to find even the point in the line where a syntax error is
detected. Old ddb just printed "Syntax error" and this was unimproved
in most places by printing a garbage token.