What

Fix the bug that the expression 42-51 fails to parse, because the tokenizer greedily treats -51 as being a number token.

Closes #133

How

Move the lexer definitions for int and float to be below the op_minus definition. This changes the precedence so that the lexer emits a unary minus followed by an integer, rather than emitting a single negative-integer token.

Update tests in src/lexer.spec.ts to expect this.

Update tests in src/syntax/expr.spec.ts to expect the resulting wrapping of integer literals with type: unary AST nodes. In particular, replace the incorrect assertion checkInvalidExpr('42.-51'); with one expecting a binary AST node because that expression is valid.

Change the parser definitions expr_member and simplestatements_set_timezone_val to parse the unary-followed-by-integer token sequence as a negative integer, as that is the only thing that makes sense in those expressions, and it limits the footprint of the change.